Brumster... You sir are a legend. I haven't yet tested it so may be speaking to soon but so far the signs are good with the Accusump in place.
I fitted it yesterday and turned the car over on the starter to prime the oil up the system and get rid of any airlocks. I then fired the car up, 50psi now holding in the Accusump over night so no leaks (Bonus).
I am just waiting on a larger bore non return valve which will arrive tomorrow to actually take her out in anger and see what's what. I am tempted to go out today for a few miles but the current non return valve is smaller than recommended as it was the only one anyone local had available. So that will be limiting the flow very slightly as its 3/8 not 1/2 inch.
Anyway, I will stop blabbing and I will let you know as soon as I take her out and see if the issue is solved.
I may also post up a thread about fitting the Accusump as it may be useful for someone else in the future, you never know.