After much tinkering (which I actually enjoyed) and draining of the fuel tank (which wasn't too bad a job), I added 10 litres of the expensive stuff and...
http://youtu.be/oap2T0UnK5o
It's alive!!!!!!!
Apologies for the wonky video, and many, many, many thanks to those who offered help. This is a fantastic forum.
I just need to work out why the windscreen wipers aren't working and it will be roadworthy after a break check.
Regards
Chris