Thank you.pskipper wrote:I had a similar problem a few years ago, turned out that the jet head on the carb was ever so slightly misaligned, not a problem when cold but once it warmed up the carb stuck solid and the car would cut out. When it cooled down again it started and ran fine. Took me ages to work it out!

On my list so far is: change the ignition coil for a known good one - a new one provided by a MM specialist.
Strip the carb.
Check the jet head and the fuel line (pump to carb) for internal collapsing.
Petrol cap.
Check all fuel filters.
If non of the above work - revert to points ignition.