After much searching I have found a suitable replacement. It is actually the offical version of the camera the makers of Ass Cam ripped off. It has a much more solid feel to it and hopefully a battery that won't commit hari kari when being changed. Even better it came with a funky water proof case so it looks like a Go Pro that has shrunk in the wash.
Coming soon to a windswept hillside near you
The new camera gets its first airing this weekend when I return to Wales. When I get more used to it and figure out a suitable mounting I'm hoping to experiment with a range of different camera angles. Initial tests show it has better picture quality to the camera it is replacing although it isn't HD quality. Better still it comes with a manual that was written by somebody who actually understands English and the microscopic buttons have labels.
Hopefully by the end of this weekend I'll have some interesting footage to post.