I have never seen anything but i did a bit of research on this a few years ago, when i was about 15/16. Me and my mates used to mess about on 'the common' not far from me. Its heavy with heather and various woodland sections. Also in-undated with rabbits.
It was in our local paper that an old woman had sighted a panther/puma/lynx or similar big black cat. And my mate whos nan lived on a farm next to the common said she had lost sheep to what she had thought must of been bigger than a fox or dog.
Anyway we researched it loads and spent hour after hour, day, night, misty mornings, foggy