Mammals

Badger (meles meles)
Although I've not seen them, there is an active sett towards the northwest of the wood. Or at least there was in 2002. I've not been in that area much since, leaving them as undisturbed as possible.
Red Deer (Cervus elaphus)
Sadly I've not seen them, but the local deer-stalker has seen them in the wood, and they are regularly seen in the area.
Grey Squirrel (sciurus carolinensis)
Widespread throughput the wood, they are regularly seen. The damage they do by stripping the bark high up in the trees is also an obvious sign of their presence.
Wood Mouse (apodemus sylvaticus)
Only indirect evidence of these. We found a number of Hazelnuts that had been nibbled by a rodent. Research indicates that the Wood Mouse was the most likely candidate. The chewed Hazelnuts were found on the bank across the track from Fernbank.
Pipistrelle Bat (Pipistrellus pipistrellus)
Seen regularly during overnight stays, they feast on the insects at The Hollies. Identification of the specific species is based on circumstantial evidence, and the use of a bat detector.
Fox (Vulpes vulpes)
Spotted trotting along the track at Fernbank by Nathanial. A classic case of staying hidden and quiet, and waiting to see what passes by.
Roe Deer (Capreolus capreolus)
I was lucky enough to see three of these all together at Fernbank. Arriving one day on a daytrip I drove down the track and slowly round the corner into Fernbank. As we rounded the corner a group of three were stood in the middle of the track. There was a couple of seconds while we all stood and looked at each other, before they moved off into the undergrowth. I have also found some of their droppings, confirming the identification.

Birds

Wood Pigeon (Columba palumbus)
With their distinctive "coo-coooo-coo" call they are easily identified both in and around the wood.
Collared Dove (Streptopelia decaocto)
 
Willow Warbler (Phylloscopus trochilus)
 
Tawny Owl (Strix aluco)
Late one evening we were sat round the fire enjoying a well-earned beer when to the south we heard the "ke-wit" announcing call. A few seconds later we heard the "koo-oooo" territorial call of a male to the north. So we know that a least one pair is living in the area.
Raven (Corvus corax)
The largest of the corvids (crow family) these are occasionally seen flying over the wood. At this distance they are most easily identified by there size, and here other birds give us a helping hand. Other species mob them, and so we can compare sizes. Closer views allow them to be identified by their diamond-shaped tail.
Chiff Chaff (Phylloscopus collybita)
Rarely seen, but often heard as they call out their name "chiff-chaff chiff chaff".
Crow (Corvus corone)
A common site just about anywhere in England, they are generally similar to the Raven, but much smaller and bolder. They are occasionally seen quite close up as they search for carrion.
Magpie (Pica pica)
Easily identified they are regularly seen in all parts of the wood. Sometimes they just sit in trees observing the world, othertimes they'll be busy flying around looking for a variety of foods.
Long-tailed Tit (Aegithalos caudatus)
A group of five or six are occasionally seen in the wilder parts of the wood, flitting in and around the thickets. Their size and long tail make them easily identifiable once you are able to catch a glimpse of them.
Great Tit (Parus major)
A common site seen on most visits. Larger than a Blue Tit, and with a black cap, they are normally busy collecting grubs and seeds.
Robin (Erithacus rubecula)
The gardener's companion seems to be able to locate disturbed ground within minutes of you starting work. Whenever any groundwork is being undertaken they keep an eye out for any worms or grubs that may be disturbed.
Jay (Garrulus glandarius)
A stunning but for me at least, a very beautiful sight. One day on arrival, driving from Lizard Corner round to Fernbank it flew across in front of the car and landed in a tree. It then hopped forwards in front of us several times before disappearing into the trees.
Goldfinch (Carduelis carduelis)
A stunning little bird, and a sign of the benefits of a managed woodland. Now that several rides and glades have been opened up, a good crop of thistles are able to prosper. Several Goldfinches were observed feeding on the thistle heads in The Hollies during late summer.
Great Spotted Woodpecker (Dendrocopos major)
Heard many times before one was seen, it was first identified by its looping flight. In then landed at the top of a dead oak tree overlooking Fernbank, where it spent some time wathcing us, before flying off. A clear example of management not being the same as total clearance, and that dead and decaying plants are as significant a habitat as new young growth.
Buzzard (Buteo buteo)
Following recent changes in farming practices, and a greater awareness of the natural world, this is now Britain's commonest bird of prey. They are sometimes seen circuling high above the valley, but one day I was treated to an extraordinary experience. Heading home one day I was driving away from Fernbank when one landed in a tree just ahead of the car. As I continued it hopped from tree to tree in front of me. Eventually it took up position in a tree in the field opposite, and watched as I drove away.
Nuthatch (Sitta europaea)
 
Wren (Troglodytes troglodytes)
One of Britain's smallest birds, but full of character. Careful study will often find them flitting around in the brash.
Blackbird (Turdus merula)
A common sight in gardens, they also provide a delightful dawn chorus whenever I'm staying overnight.

Amphibians & Reptiles

Common Lizard (adult & young) (Lacerta vivipara)
A real surprise, and all credit to Will and Nat for spotting them. On the corner between the main drive and The Hollies a family were spotted sunning themselves. By the time I'd got the camera the adult had disappeared but the young were inquisitive enough to remain visible.
Common Toad (Bufo bufo)
Another visitor to the campsite. Found lurking behind the tent walking ariund in the long grass.

Butterflies & Moths

Small Tortoiseshell (Aglais urticae)
With it's eye-catching orange wings it is easily seen, but difficult to study as they are so active. Now that the main drive has been opened up and sunlight can reach the ground, various plants have grown up that are providing food for a variety of insects, these included.
Red Admiral (Vanessa atalanta)
Easy to identify by it's black wings with a single large orange circle encompassing both wings, these appear in the wood in their dozens, feeding on the Hemp Agrimony.
Hedge Brown / Gatekeeper ♀ (Pyronia tithonus)
As their common name suggests they are normally found patrolling hedges, and are often seen defending their territories from neighbouring rivals. A gateway makes a natural division between territories, and so they tend to congregate in these areas.
White Admiral (Ladoga camilla)
 
Speckled Wood (Pararge aegeria)
During summer days they are easy to spot as they bathe in the sun along the main drive.
Peacock (Inachis io)
Arguably the most spectacular of all butterflies. Only ever seen in small numbers, they take advantage of the nectar provided by the Hemp Agrimony on main drive.
Common Blue ♂ (Polyommatus icarus)
Small, nervous, and fast moving, this one took a while to positively identify. Not often seen, but when they are they tend to be patrolling the grassy area near the main gate.

Other Insects

Common Hawker dragonfly (Aeshna juncea)
Only 99% sure of the identification here, as it wouldn't settle long enough to get a good view. Patrolling the area around the main gate it was obviously on the hunt for a good meal.
Southern Hawker dragonfly (immature) ♂ (Aeshna cyanea)
Spotted this one as it patrolled the main drive close to The Quarry. Eventually it settled long enough for me to get a picture. Identified not only by its general appearance, but by the joined-up yellow patches on the end of its tail.
Beautiful Demoiselle damselfly ♂ (Calopteryx virgo)
Living up to its name this damselfly appeared one evening in The Hollies, and settled on a tree for the night. The light had faded too far for me to get a picture. However the following morning it was still there, and remained so until the sun warmed it up and it was able to continue on its travels. As it was some way from any water, it may have been in its Teneral stage of development.
Large Red damselfly (Pyrrhosoma nymphula)
Didn't get a picture, but being bright red I'm reasonably confident about the identification.
Cockchafer beetle (Melolontha melolontha)
A lesson in always having a camera with you! Discovered on some brambles on Main Drive I realised that my camera was back in the car. I noted the antler-like horns and then went to get the camera. By the time I got back it had gone.
Hoverfly ()
Very common, being seen on pretty much every flower that's out in the sunshine. There are so many species that's it has been impossible to identify them specifically.
Rhododendron Leafhopper (Graphocephala fennah)
Discovered this little beastie taking refuge inside my tent. It looks similar to a Shield Bug, but has reddish patches on its back.
Striped-winged grasshopper (Stenobothrus lineatus)
After hearing it for several hours, it eventually showed itself, and became quite friendly. Happy to let us study it, it spent quite a while relaxing on the picnic chair.
Sheep tick (Ixodus ricinus)
Ben and Josh found these! Thanks to Barney for showing us the safe way to remove them. They would have come from the deer that inhabit the wood.