There is a breeders list on the Northern Hamster Club site here
http://www.northernhamsterclub.co.uk/breederslist.htm
I would suggest either Midnight Stud, Cheverton Hams or Duncton Hams who breed these or if you can look at the show list there are normally good quality babies on sale at the shows. If you contact the breeders beforehand they can often bring you whatever you want to collect at a show.