Try
http://www.champdogs.co.uk click on Guided Search, then Gundog Group, then English Springer Spaniels, then breeders and it will give you a list of breeders with their areas.
If you are prepared to travel to Norfolk, then I can personally recommend Colin and Carolyn Muirhead (Shipden English Springer Spaniels). They both work and show their Spaniels, and do all necessary health checks. As well as breeding their own lines, they also import from abroad to improve their lines and working ability. They will offer a lifetime of advice and will be more than happy to keep in touch, and will even trim dogs bred by them if you bring them to see them. Their telephone number is 01263 761319.