Here is the part that's not funny. The engine is fixed. It took forever to find out what was wrong and I came within an inch from breaking it after rebuilding it.
A previous "technician" had been at it and one of the two 4mm o ring's had fallen off the back of the enrichment valve where it attaches to the bottom carb. It was by pure chance I found this and if It was in commercial premises the bill would have been more than the engine was worth. It's certainly one for the memory bank.
