Firstly thank you for all your suggestions and ideas regarding this P.I.T.A. problem
I decided to go back to basics and check absolutely everything.
Without the engine in the bike getting at the pipes to the tank is easy so I blew the return line out and can poke a bit of cable up it easily actually being able to see the end of the cable coming upp the return pipe in the tank. I also blocked of the return in can the tube in the tank was cracked low down, stuck at airline on it and am totally confident that there is no blockage or restriction of any kind.
Next I checked the bolts that hold the rocker box feed to the head, the flow holes in the bolts actually seem to be slightly smaller than 1/64 so I know its not getting too much oil up to the rocker box and consequently flooding the sump that way. I am unsure if I should actually drill them out to 1/64 I am still thinking on that one.
There are very few oilways in the crankcases but blew them all through thoroughly, again no sign on any restrictions. Having removed the scavenge pipe that is also clear and good. Blow one way and the ball seals blow the other and there is no restriction at all. I even heated it with a blow torch to make sure there were no cracks that I could not see that might cause the problem.
The oil pump I have sent away to be tested and I am waiting for an update on this.
The oil pump gasket is an SRM one so it does not need the washer under the pump at the front but when the pump returns I will be checking the seating of it. I aim to bolt it on the right hand case so that I can blow all the oilways when it is in situ to check that it is seating correctly.
The next stringent check will be to make sure that it in engaging correctly with the crank and the worm drive.
I have also extended the breather pipe coming out of the crankcase so that I can actually put a rubber pipe on it and wedge it into a container, just so that I dont get covered in oil again and if it does pump out I will at least be able to measure the flow coming out of the breather.
Once all these tests have been performed and hopefully passed I will bolt it back together. Should it pump oil out of the breather AGAIN I will then have a full ceremony where I will douse it in petrol and happily set the damned thing alight.
I will be purchasing a few things off Andrew at Priory, new PRV ball and spring, gaskets etc etc.