uriel13 wrote:
It could be a Cleg, it is approximately 3/8 " long, black outer casing
on wings, red body and legs and red head. It is quite thin approximately
1/8", it can give a nasty bite. Does this sound anything like what you
saw!

Hi. Thanks for the suggestion (which was vaguely amusing, as I was getting
a mental image of an insectoid Nick Clegg hanging about my window!), but I
think the earlier suggestion fo an Ichneumon Wasp is the right one. After
15 pages of images, this is the one closest to my beastie:

http://www.insectoid.info/thumbs/607.jpg