Hi - Chippenham way?
Its not very close but when I lived in Hungerford, Berkshire, I used to go to Kintbury & District Working Gundogs - they are based between Newbury & Hungerford at a Keepers property. Do all gundogs but a high proportion of cockers & springers. The ground is fantastic as it is on a shoot so you get to experience everything, there is a rabbit pen, woods, long tufty grass areas, everything you could want for. They usually do the working gundog demonstrations at the Newbury Agricultural show which I think this year is the 18th 19th September. They meet the first Sunday of every month at 10am and then during the summer months on a Wednesday evening. Really friendly and knowledgeable. Its about £15 to join for the year and then a nominal fee per dog at training sessions.
Fraid I don't know anyone closer than that but if you fancied a good day out to the Newbury Show (dogs not allowed unfortunately) they usually have a little marquee and you could get alot of questions answered.
Good luck!