well
the education authorities have published a lovely little list, in order of difficulty, and latin is hardest, no doubt about it. others at the top of the difficulty scale are languages, sciences (exc. biology), and stats
i think it goes:
latin
chemistry
physics
german
french
spanish
stats
or something like that. easier subjects are the usual suspects; drama, PE, textiles, media, office tech and home ec. also on the list was english, which i suppose makes sense (english does not equal literature, that's a completely different kettle of fish. it's referring to english language, which is a very easy GCSE)
personally, it's chemistry. i only find biology, art and german difficult because i don't really care. maths is easy if you remember your stuff, and as long as you can remember the equations, physics is piddle at GCSE. imo, anyway.
can't speak for stats