thanks everybody! Seems like this is a pretty contentious area, so some more reading to do, but I guess I may be stuck with the car until a year or so, and then again with the next one.

Thanks squirtday I'll have a look at www.bhsi.org , and at that sticky, the helmet thing is at least as contentious as the baby thing. I am also going to look for stuff on holland, they havent all died despite not wearing helmets, but why is that? It could be safety in numbers, which doesnt help individuals until everyone else starts cycling.

thanks again, very helpful