2007 mk7 fwd 2.2 tdci poor starting

[Rollingbob]

Hello again. Hope all is well,

Have a 2007 Mk7 fwd 2.2tdci which now has poor starting Have tried new starter, battery, crank/cam/maf sensor, fuel tank sender unit, fuel filter (put vaseline on all the pipe connections too but does still go quite empty), fuel filter housing...alternator working, no codes showing, grounds all good, Glow plugs all good, Compression all good...

PRV isn't leaking should I still take it off to see it its in pieces?

I'm getting ~4350psi on start up - so does start but then struggles to re-start after driving for a bit. If I put a power pack on it, it always restarts.

The fuel filter immediatly empties to about half full. Which I'm pretty sure it didn't do when it was ok.

I thought it did have fuel pump fuse and relay - that's what it says in the book - no.7 engine bay fuse box relay although mine is indeed empty of metal contacts. The book says fuel pump fuse is its no.27. This is briefly lighting up with a test light with ignition on, but then goes put. All other fuses in engine bay good.