Many thanks.
I tried 7zap earlier today but the image was completely garbled for some reason..
BTW.. I have discovered another trick... If I just turn the ignition on and off (without starting the engine) twice and then turn the engine on, the car starts up and drives well. Sometimes the engine surges from 800 to 1100 rpm when idling, but otherwise OK..
It's definitely pointing to a problem pump or return valve...