I know thats one reason, but as I have been through two new factory cylinders it would point towards it not being in this case. Unless I am destorying the cylinders in the bleeding process I dont think its the culpret.

There are multiple scenarios that could theoretically cause this it just a matter of comming up with procedures to eliminate each on in turn.

I think my next move will be to 'blank' of the master cylinder from everything other than the master cylinder to try and pin it down the one of the two units and exlude the rest of the braking system. Does anyone know a good method of blocking the holes in the master where the brake pipe flanges normally go. I dont just want to screw a bolt down in the event I damage the flange. Once again any advice on this much appreicated