I spotted this circle whilst out cycling this evening. It's north of Weston Turville, Bucks, on New Road on the right-hand side from Weston Turville to Aylesbury. I've mislaid my OS map of the area, but when I track it down I'll send you the map reference.

It consists of a small single circle (I didn't measure it - 20'-30'?), in very ripe wheat. It's just about visible from the road. 

All crop spirals clockwise from the centre, with some swirl to the lay, and some evidence of layering. There were also a number of standing stems. There was some breakage to the stalks, though the crop was extremely dry and brittle.