Try this place:
http://www.safety-marine.com/sm/dept.asp?dept%5Fid=9
Good prices for good kit.
I got the £42 one and it seems pretty good. I'm not a paramedic or anything dramatic like that but it is a lot better than nothing. I've added a bottle of eye wash, more TPAs and put the whole lot in a "flare box" to keep dry.
Also a strange one but I have a roll of electricians tape to wrap round little cuts. Plasters are rubbish when your hands are wet and this does the trick!
Chris