There was one on Bodmin Moore in Cornwall as well.
Back in the very late 1960s and early 70s, it was possibly to walk into Harrods of Knightsbridge, and buy some very exotic animals, lions, tigers, leopards, within reason anything was available for the wealthy clients wanting an exotic pet.
Thankfully such poor regard for exotic creatures, is a thing of the past, but there is a very good chance that a very small number of these unwanted pets were released into the wild.
Back in the 1990s, there were a number of sightings, and possible photographs of large cats, particularly panthers, in the South of England, Dartmoor and Bodmin due to their size and remoteness, were known hot spots.
Nothing recently has been reported, so the number of creatures must have been very small indeed, but there's a good chance one or two of these wild cats still roam the English countryside.