The first Wonders series was re-run on BBC2 this week. I didn't catch it the first time round, but my mind-boggling respect for the second series meant I just had to watch the first. Due to the time difference Wonders of the solar system was broadcast at a hideously late hour, thus necessitating recording (which I was planning on doing regardless of the time) Anyway, I watched the first episode and there it was: the answer to my question about the birth of our sun. And that's why I love physics... classic tv moment of the decade, by the way; even better than the total solar eclipse.
What do you know? It was a swirling cloud of matter just hanging around in our part of the galaxy waiting until things starting getting heavy enough for gravity to do its thang. After that it was just a case of 'we have ignition!' and the lights go on for the next 10 billion years. Glad I'm not paying that celestial electric bill.
So it's a big thank you to @ProfBrianCox for answering my question before I even knew I was going to ask it. Who says Brian Cox doesn't know everything? Top bloke, even if he is an uncaged northern monkey.