Well it's back and too make sure, swapped the 500w psu for a nice 750w Model HP-750-G14C+ specs ..
+5v 30A and +3.3v 28A = 180w
12v1 18A and +12v2 @ 18A and +12v3 @ 18A and +12v4 @ 18A = 650w
-12v @ 0.8A = 9.6w
+5vSB @ 3A = 15w
Plugged in the basics and even used the nice 8-pin cpu power lead and the extra power molex.
Nothing, lights go on, fan spins and it just sits there.
Remove memory, detects its missing.
Remove GPU, detects its missing
Make sure CPU isn't fubar, plugged in a Celeron 3Ghz from another PC, nothing.
Plugged in generic working DDR-800 and NV6200, nothing.
According to GB and I quote email "We advise this item has been tested with no fault(s)/errors found on our test systems", yet paper work says error P06 system no boot no display.
So am I wasting my time, a little disappointed nothing could have been done for something a few months of our warranty if I understand the way the serial number determines this, waste of another £11 sending it to GB.