Just been out to change the oil, air and fuel filters. All went well, started her up again, got a few hiccups 'cos the fuel was empty, but it didn't stop then went for a drive round the block, all fine. So stopped, turned ignition off. Sat for at most five seconds, started it up again, started straight away no hesitation so turned off ... Pulled key out, but took a second to realise the engine was still running!
Put key back in, turned to on, glow plug lights came on, let them go off, turned off and removed key and still running again!
Key back in, turned on then off again and this time it stopped ....
What gives? Anyone any clue. It's never done this before.
My best guess is that the ignition circuit is still 'live while the glow plugs are warming up and 'cos the engine was cold, the plugs were staying on longer, hence keeping the ignition circuit live until they got hot enough to shut off properly. I haven't convinced myself that's correct though .... ;)