Anyway, had been toying with the idea of getting a raspberry pi running xbmc setup in the car. Anyway, finally had a dry day, and here are the results...
OpenElec booting up

XBMC booting up

Option screen to select the kids profile

and finally the media centre loaded

Currently its powered by the cig lighter socket, but will do more perm soultion later. Just wanted to make sure it worked. Plus it means no more getting out to change films and it is all controlled by a IR remote.
Happy days and happy kids.