Try Aeros in Gloucester or Bristol Flying Centre . Both good, dedicated modular schools. You will, I imagaine, get lots of replies giving good/bad comments on several schools. Your best bet is to make a shortlist, visit them all and come to your own conclusion. There are also numerous threads on this topic here.
Having been through the system the only advice I would give would be wary of very small schools whose financial stability could change quickly, or very large schools who also offer integrated courses.