the 1990s surveys suggest it might have been fatter in places, but not with a different alignment of limb.
they also suggest a longer "beak" feature, which would only give more weight to my vision of synchrony between them and the salisbury river fork.
There is no reason at all to compare it with the earliest known paper maps of britain, since it was made 2000 years before them, and, as you have observed, they are not all that good.
imagine the sense of awe when the people realised, after decades of integrated fieldwork, the island they lived on kind of looked like a horse. the birth of a national myth. perhaps THE birth of national myth.