No one can make this decision but you.
I graduated from Manchester this summer and whilst I never did Chemistry, there's so many people around that from a social side of things, you're almost guaranteed to have a good time just through the sheer number of people around.
It's a good university with a good rep and an even better international rep. Employers tend to like Manchester graduates and have a favourable opinion of them for those looking to go into high salary occupations - finance, law, management schemes and engineering.
Also a good base for a postgrad course at Ox/Camb