
Ah, that makes total sense then. Yes, it is easier to collect if you can bring an in-season bitch with you.
I don't know about specific areas, but UKClone and Fit & Fertile were two I looked into when I was researching.
I went to a reproduction seminar led by Angelika von Heimendahl who is a repro specialist and is based at VRS (Veterinary Reproduction Service) in Cambridge.
I basically did a google search for Canine Reproduction or Canine Artificial Insemination and found several links at the time which I followed to get more.
Best of luck :)