Thanks for the comments.

I've secured the heat shield so that it doesn't hang and rest onto the spade of the starter motor. Access was very difficult, but when I removed the spade, I noticed that the insulation close to the connector, and where the heat shield would have been in contact - was a bit melted. So - that could well have been the problem. No corresponding black mark on the the heat shield though. It seems to be starting fine at the moment now that I've wedged the shield up, so I just need to use it a bit more and get some confidence back. I'll just make sure to park facing downhill for a while when I'm out and about.

While I was trying to get access to the starter connections, I removed the 2 muffler end pipes, and afterwards, I fitted the straight through versions. They make things quite a bit louder and actually change the behaviour of the car. It's a bit more responsive, seems to rev more freely and doesn't like being below 3000rpm (previously, I'd have put the threshold at 2500). It might just be me, but that's how it feels.

I think the mufflers will go back on before I go to Prescott again this Sunday.

Cheers - Justin.