Hi,
Don't know about light aircraft, but the BMAA magazine lists the type and number of all microlights in the UK (flexwing and 3 axis). Since 3 axis microlights are becoming very popular, and pretty much nowhere has them for hire as it was illegal until very recently, there are quite a lot of syndicates for microlights.
Not sure if you can get the info directly from the BMAA, but I suspect that if nothing else, they would send you an example mag, or someone who is a member can (I may have a few to get rid of soon. Just catching up on reading!).
IPZ