Hmm, well it turns out it was a sticky solenoid that eventually broke. They fixed it under warranty, so no charge. I suppose I should be grateful.

Just got to dismantle the exhaust again now and re-assemble with paste to achieve silence and more than 15mpg, as they didn't put those stupid sleeves back together properly again so it's blowing like a tractor.

Then I've got to clean the black hand prints off the boot and bonnet.

Thought I'd be happy to get her back, but she's lost some of her sparkle in my eyes after all this recent unreliability