I've been trying to make my own lowline sump based around the three links below. Using a steel sump to chop and modify it's looking not to bad but I wondered how high to make the internal baffle. Anyone care to comment?? I reckon the baffle in the sbd sump is around 30mm above the base of the sump. But I'd like some second opinions before I go any farther in the process.

westfield sump
Caterham sump (no baffle but they do a foam baffle?)
Sbdev sump

I can't really be specific, but I use the caterham one you have linked above, with foam insert (which they do sell as well) and its just held in by the std vauxhall windage tray, which you definitely DO want!

The whole sump is only about 50/60mm deep internally