I've done my searching, and stuck with "plan A". I've ordered a Canon 8400F. It looks like this is about to become a discontinued model and people are lowering prices to clear stock. This is the ideal time to buy things in my book, you get excellent value for money.

I was surprised by how few stand-alone flatbed scanners there were in PC World, would have expected a much bigger range but I suppose they are unfashoinable, replaced by multi-function devices. Didn't buy from there, way too pricey!