If you can bear to pick it up, and are planning a trip to visit the museum anytime soon, you could always bring it along to the Angela Marmont Centre. They offer a drop in service for identifications, all information can be seen here:
They will be able to give you a more definate identifcation.
perhaps this link may help?
it lists most of the fauna of ashdown forest, i know theres a few different species of deer or is there any chance it could be a badger? just a thought