The Anglian ice sheet base

This is a reconstruction of the position of the NW European shoreline at various times following the breakup of the Devensian British / Irish ice sheet.  The outermost shoreline represents the situation c 18,000 years ago, by which time the ice sheet had reduced greatly in size.

Not much time and effort has gone into reconstructions of environment at the time of the Anglian glaciation, around 450,000 years ago.  Was the sedimentary makeup of the North Sea and the Celtic Sea very different from that of the present day?  In some places there are great thicknesses of glacial sediments, with a rock floor which is well beneath the position of the present sea bed. So the Anglian shoreline may have been closer to the position of the present British / Irish shoreline.  On the other hand there may, at the time, have been thick sea-floor sediments derived from even earlier glacial episodes.

It's probably best to assume that the Anglian shoreline was not too far removed from that shown in the map, and that the ice sheet was able to grow as a land-based system, without any interference from ice flotation and assorted other interactions -- except, maybe, for the far NW near the Hebrides, where the sea floor plunges steeply out into the Atlantic.