Well it lives!
I found a suitable woodruff key in the shed, put it together and pulled a good 15-20 times. Nothing. Not a cough, not a peep then I realised that I hadn't reattached the HT lead

Attached the HT lead, one pull and away it fired. It's only running on start ya bastard at the moment so I need to clean out the carby but looks like it'll be fine once that's sorted.
They sure as anything don't make 'em like they used to!
This one will be cleaned up and stored away in the shed - never to cut any grass in real anger again.
Thanks Gadge and Jack for the help.
I'll try post a video of it running when I get a chance to clean out the carby (Hopefully either Sunday morning or Monday).
Pete