The first half of the episode was, by far, the more fascinating. Although, I'm a little disappointed by this apparent rule of "Debunk-it-in-three-tries-or-else-forget-it." As I noted elsewhere, the TST's in episode 2 could have been costumed stilt-dancers. And, Jael's trio should have investigated that possibility. So, too, with the Beast of Dartmoor, was there a fourth possibility they didn't investigate.
The feral mixed-blood progeny of big cats illegally released from private menageries! In this case? A possible hybrid of cheetah and black panther.
Just because the British government publicly states there is no such thing roaming north-central Britain doesn't make it so.