Well, I'm in two minds about posting this but decided that if I can prevent anyone doing the same stupid thing that I did yesterday, then it is worth the humiliation that posting this might incur...
While out searching for Morels to photograph, I was in and out of some scrubby undergrowth on Stockbridge down and I spotted a tick crawling up my trousers. As I got back to the car (another unsuccessful search I might add, Morels are tricky devils to find), I remembered to brush off my clothing. The camera was around my neck so I slipped it off and rested it on the roof of the car. You can see what's coming...
I put my camera bag on the back seat, took off my jacket and hung it over the open car door while I brushed my top and jeans off. Before stepping into the car, I took the jacket off the door and put it onto the passenger seat and, with the attention span of a herring, got in and drove off.
It turns out that a 40D will stay on the roof of a Mazda 323 until you get to about 60mph

Stupid stupid stupid momentary lapse in concentration.
Bill