Ilfracombe erratic spread

The plateau behind Berrynarbour -- erratics up to 175m?

I'm intrigued by a statement by Prof Nick Stephens that there is erratic material in the Ilfracombe - Berrynarbour area, on the plateau to the south, up to an altitude of 150 m - 175 m.  This is recorded on p 202 of the 1998 GCR volume on The Quaternary of SW England.  I have not been able to find further information on this -- but it would not surprise me to find erratic boulders and cobbles up there, and Nick Stephens was a very good geomorphologist who would not have said anything without firm evidence.

This of course points to a considerable incursion by Irish sea ice across the Devon coast, thick enough and extensive enough to affect the Barnstaple - Fremington area, the Saunton-Croyde area and to have dumped the Shebbear erratic more than 20 km south of Ilfracombe.  Indeed, it would be extraordinary if this ice did NOT overtop the cliffline and press well inland, since it was able -- on at least one occasion -- to flow over Lundy Island to the west and over the islands of the Scilly archipelago, far to the south. (I demonstrated that in my research on the Isles of Scilly some years ago.)  It also makes sense for Irish Sea ice to have impinged upon Exmoor and to have had an upper surface at maybe 200m, since it did at one time extend another 60 km to the east -- leaving till at Greylake, in the Somerset Levels.