First rule of wine circles...do not talk about wine circles.

Hi Matt,
A wine Circle is usually formed by a group of people  with wine/beer making interests and as a hobby, where they meet, taste, discuss and exchange recipes and ideas, as we do on here .
On occasions there are connected to a local horticultural/allotment group and if sufficient "circles" in a large area e.g. Norfolk they may become affiliated to the NAWB (National Association of Wine and Beer).
In addition to wine making and tasting they may get involved in other social activities, having guest speakers, competitions , vineyard visits, games and quiz nights .

When you've proved you can make wines and win competitions, have stewarded for qualified Judges at recognised competitions, you can then apply to go on a course, usually run by the senior qualified judges to take either the Federation Wine Judges examination, or the National examination, held twice yearly..
Have a look on the NAWB site to see if you recognise any Circles near you..
You already have a few contacts, if going forward have a note posted in your library and your local paper (not a paid advert), also in your Home Brew Shop, Wilkinsons , The Range, Holland & Barratt and Tesco.
Good luck, if more info needed ask away....

F.t.