Fuel Pressure Regulator failure

Hi guys, the fuel presure regulator on my 3.9 Disco has failed after less than 1 mile. The car has just had a top end rebuild with new injectors and new regulator (amongst many other things), and was running perfectly. Now it won't start, no surprise there as fuel pouring out of the vacuum pipe outlet back into the plenum when the pump is on.

Has anybody else had this experience?
Was i foolish in putting on a Britpart item?
Is there something else underlying that I should be looking for?

I've ordered a Lucas part in the hope that this solves the problem, but I can't believe a diaphragm would fail so quickly.

Not so dramatic as your experience, but I tried one of those much praised 'variable pressure' units on my 3.5efi a while back, can't remember the maker, but it lasted less than 500m so I went back to the original PR. You live & learn!