the carpenter who is going to replace a window for me doesn't seem concerned about the asbestos sheet on my house either. The guy that did the analysis said don't worry about it unless it starts crumbling.
and silent c one of the things that is lurking in the roof space is lead ... this is a link which mentions it in passing but a bit of a search reveals a heap more :-
http://www.abc.net.au/science/k2/trek/4wd/lead3.htm
There are actually people who will go up in your roof space ( through the roof tiles/sheet ) and vacuum it out.
If you have, as I do a house with 40 year old carpet in it then that is probably full of the stuff too, partly from them rubbing down paintwork in the past and partly from cars. If I had small kids I'd be ripping the carpet out, at the moment at least its inuslation :-).