This is a topic to which we have returned many times, and will no doubt return again.......
I have been taking a fresh look at the highly influential paper by Patton et al (2016) which applies a more sophistcated modelling technique than ever before to the Eurasian ice sheet complex -- including the Celtic Ice Sheet (otherwise called the British / Irish Ice Sheet or BIIS). Although the work relates to the climatic and other conditions for the Late Weichselian (let's say 40,000 BP to 15,000 BP as being relevant to SW Britain) the modelling is in some respects more applicable to the earlier glaciations, since ground truthing suggests that the Celtic Ice Sheet never did develop to the full extent as predicted by the model.
The map above shows the most commonly assumed Devensian ice limit (red line) for the British Isles, which is clearly inadequate in many respects. The area defined by the wavy dark blue line shows the maximum extent of the modelled ice sheet, based on an analysis of a vast range of different parameters. The orange areas are the areas of assumed highest erosion -- the dark blue area shows the ice shed location, stretching from the Lake District across to the Isle of Man and thence towards SW Ireland. Note that the ice is shown impinging well into the counties of Devon, Cornwall and Somerset, onto Salisbury Plain, and across the Midlands towards The Wash, incorporating a large area to the north of the Thames Basin assumed to have been unglaciated in the Devensian.
Take a look at these maps as well:
The similarity between these maps is remarkable, given that my map is based largely on ground evidence, and theirs is based on computer-based glacier modelling.
So far so good -- but the intriguing thing is that my map shows my assumed Anglian glacial scenario, and theirs shows a theoretical Late Weichselian scenario! I need advice from the experts. Watch this space........
Henry Patton, Alun Hubbard, Karin Andreassen, Monica Winsborrow, Arjen P. Stroeven. 2016.
The build-up, configuration, and dynamical sensitivity of the Eurasian ice-sheet complex to Late Weichselian climatic and oceanic forcing. Quaternary Science Reviews, Volume 153, 1 December 2016, Pages 97–121
Note: Late Weichselian = Late Devensian