The more I think about it the more it seems to be the fuel pump or perhaps the relay. Unfortunately the pump is quite expensive so I've been hoping that it was something else.
I just syphoned some fuel out of the tank and it was crystal clear so I dont think theres loads of crud in there.
As for the regulator, the problem isnt brief and once the hesitations started its there until I stop the car.
I would like to get the fuel pump relay out to check the solder joints but its hard to get at behind the CPU & the ABS computer.