Might be an idea to check out Cheddar Gorge at some point? A long shot I know but it does have a past track record for montane species.
Two went over my house last Friday in Minehead at 6 p.m. whilst I was doing some gardening. Both birds came from the south. One of them gave a good view as it swept round in a circle almost directly overhead and flew off east.
Tweet suggesting 2 seen on right side of border over exmoor last Friday