Well I decided to bite the bullet and give it a go..... Now posting this from Firefox within Ubuntu
Not dropped back to Vista yet to see if it will still boot okay, but at least got this far.
A couple of issues at the moment, like that the install does not see my second monitor at all, and that the sound level is stuck on full volume which is scary..
At least the rest of it seems to be there. Now I've got it though no idea where to go from here!