Not good news, I have done a scan on our database under that engine code and have no information which does not surprise me! The distributor part number may have provided an avenue.
I reality I dont think at this point you are going to be going to Glasto in the Bongo tommo so maybe your efforts would now be better spent seeking alternative transport and on return booking into a garage specialising in diagnostics.
It may be that this could be solved in time by anecdotal diagnosis, to do that you need a lot of suggestions and unfortunately a lot of the troops are probably on their way to the Bongo Bash.
Any how if you have a bit of time go for the obvious.
Carry out the checks yourself as to the spark, fuel and air/ vacuum pipes as described.
Read trough this post it describes how this guy gained access the air screw valve
http://igmaynard.co.uk/bongo/forum/view ... =3&t=71967.
Check the ignition system.
Remove the dissy cap and make sure the carbon pin in the center of the cap is there and free to move.
look for moisture in the cap and body. Carefully dry with a hair dryer if moisture is present.
Check all the ignition leads especially the center lead and clean them with nail varnish remover or a solvent fluid (allow it to evaporate after) leave them attached else you may get them muddled. Look at where the king lead comes from the coil and ensure that area is clean look at all the low voltage wiring to that coil and ensure the terminal clips are clean and secure.
Now inspect all the ignition leads for cracks or damage especially where they pass by metal.
Clean the crank sensor and carefully check the wiring for cracking follow it back up the wire.
Remove the spark plugs and check the ceramic areas as well as the electrodes. just the easy ones for now.Clean the ceramics and stick them back.
Did that help?
More questions now.
Did the AA guy or whoever it was that checked the spark and fuel, at that time was it running, if not how did he get it get started?
Did the other garage guy who did the clean up ,code read it?
How are you with multi-meters and do you have a digital one or better still an oscilloscope.
You will need these if you are going to work through the system as well as data and time and the last one is probably the big issue.
Keep me posted.