Here is a great article from another breeder on how to find a good breeder and also the best way to approach a breeder. Article is here
Please be aware there is a couple of Back Yard Breeder breeders in Doncaster so please be very careful make sure you fully question any breeder. One who is in fact telling people that their rat had a accidentally litter. Please be aware some breeders may care for they rats well but it does not mean they know anything about breeding rats.