After-all, their MChem program is offered by the School of Life Science, not a department of chemistry.
I don't think that's necessarily a problem, my Chemistry course is offered by the School of natural sciences - department of chemistry is just a department of it.
The best thing to do is, as Geo said, ring them, definately visit at some point and
talk to the students. The University want your money and are not going to turn around and say, "yeah, actually the facilities here are pretty poor."
Also, seeing as you get 6 choices, you may as well apply - you can always decline an offer later.