I'll Google this too, but since searching for DVD information isn't always easy (for me anyway) I thought I'd ask here to make sure.
I already have the first G1 movie (the "smooze" one) as a gift from a friend, and I would like to get more stuff. G3 is probably what I'd be most interested in, followed by G4. I don't think G1's "Rescue at Midnight Castle" is out on DVD, but if it is please say.
I think UK region is region 2 or PAL.