when last checked my fuel pressure at idle was around 3bar, revving the engine gave a reading of 3.5bar.

A fairly basic way to increase the pressure from normal is to use a centre punch and hit the centre of the original regulator without breaking it and basically checking the pressure again with a stand alone gauge.

Its not the most professional way to do it but a small increase in pressure was the result.

I should say, this was only done for a short period, tests etc, I now have a proper pressure regulator.