[Suggestion: It might be useful if people reply to TSS's first post at the start of the thread, just to make it easy to see what's a vote.]

Mine are:

1. Nine Maidens stone circle, Boskednan, Cornwall

http://www.themodernantiquarian.com/site/239/nine_stones_of_boskednan.html

2. Tregeseal stone circle, Cornwall

http://www.themodernantiquarian.com/site/241/tregeseal_stone_circle_and_carn_kenidjack.html

3. Doll Tor stone circle, Derbyshire

http://www.themodernantiquarian.com/site/469/doll_tor.html

This is really tough! Apologies to Gloucestershire too.