For the 44th Foot, I have seen a transcript of a so far unpublished letter from Sgt Major William Roworth who describes how his brigade marched with Abercromby on the night of the 14th/15th, significantly he also describes the positions held by the French infantry, which implies that the 44th weren't simply guarding the route back to Berlicum.

Hi Garry

This letter sounds interesting - where did you find it?

Regards

Paul