Details below. I've been quoted $47.96 for a group buy, which according to my untrustworthy on-line converter works out at £23.52 (the price in sterling is just a guide and not the actual price).
The tarps are direct from Hennessy but they have some stored in London so we won't have to pay customs and the postage will be a lot less. According to my calculations it should cost £33 all in.
70D "HEX"-SHAPED PU-COATED POLYESTER RIPSTOP RAIN FLY
Size: 132"x 120" hexagonal shape Weight: 1 lb. 9oz , 700 g. This fly comes standard on the new Safari Deluxe but will provide generous protection from wind and rain for any model.