Back to basics. The battery. Sorry. It's long past its End of Life for the M3W. The stock battery Morgan supplied is well and good for large lawnmowers and the like but four years is way too long. I keep coming back to the fact that when this engine is warm/hot it is really harder to start. The compression numbers go up as the seals get tighter. and they do.
Mine could not cut it when it neared its time. Cold starting was fine but when the block was hot then forget it! Bikers all shook their head in agreement. "It may overheat in traffic but if you shut it down then you will have the devil's own time turning it over!"