Matt,
Find your local Prochem distributor, they do a good solid range.
Mike Boxall who sponsors this site ,click on the link below the blue Cleanitup , sells Prochem .
Alltec and Extracta do a good range.
You also have Solutions and Hydramaster in Cornwall.
One word of advice ,it's not necessary to carry hundreds of chemicals , get the basics and add as you go along.
Cheers,
Doug