Does anyone know of a suitable yorkshire terrier stud in or around the Preston?

That will depend entirely on your bitches faults and virtues and that of her bloodline.  It is important to know these things before considering breeding.  Obviously younwon't have perdonal knowledge fo the dogs in the pedigrees to amke informed decisons so you should contact those who do which is likely to be your own bitches breeder (if reputable and knowledgeable) or the owner of your bitches sire.

Contact the breed clubs for more information, as to when they are orgaising shows so y9u can see the dogs, what their offspring are like and meet breeders who may be able to help you.

Your bitch will need to be independantly assessed to see if sheis of breeding quality as well as have an breed specific health tests carried out.

It would very much depend on the lines your bitch is bred to as to which dog would be the most suitable - your dogs breeder would be the first port of call for advice.

She should be ideally KC registered and of course the sire too.  I presume she's still only young with you asking for dog training places too?  She shouldn't be bred from until at least 18 months I would of thought. 

As others said most of us travel quite a way for our stud dogs, some of us even have on loan stud dogs from another country :d