Hi Marty, all usual stuff checked and/or replaced.
New glow plugs and tested all ok.
New prime pump.
New fuel filter. (bleed screw seals ok)
New blee3d off pipes.
No sign of failed fuel lines.
Now, the reason I suspect fuel draining problems is this:
Car running normally and hot or cold, turn off engine, within 5/10 minutes car will be hard to start just as if air is in the fuel, it fires while on the key but needs full throttle and then runs rough and clears to run normally.
Now what I discovered is that if I simply blip the throttle and turn the engine off while the revs are at 4k then the next time I start the engine the car will start instantly and normally up to a week later! I have tried this many times and the result is always the same.
This makes me think there is a dodgy non return valve somewhere, the primer pump is new so it's not that one.....
That's as far as I can go, I have heard there is a valve in the fuel pump but I don't want to tackle that if it's a hard job, I will live with the fault rather then throw money at it, but if I can do it myself I will.
Thanks for your help.