sacrilege though it may be I used my car to block my driveway for a few weeks whilst I awaited new gates to be built.

took her out for a spin and a refuel yesterday now the gates are sorted

when I flicked the fuel over to LPG I noticed a smell of petrol immediately so pulled over

petrol was leaking from a point inboard in front of the nearside rear wheel

on a hunch I switched the fuel system back to petrol and the leak stopped

obvs I'll get the car booked in to see Hiltons but wondered in anyone had any ideas?

Strange, it shouldn't make any difference as petrol continues be pumped through the fuel system the normal way even when using LPG.

my monies on it running slightly higher pressure to the petrol fuel rail when on lpg and you have a pinhole leak thats only evident when the petrol system is running when not on demand , once you go back to petrol the fuel rail pressure drops by just enough to stem the leak

should be easy to find the leak anyway.

Some fitter run a line back to the tank so if on gas it will pump a loop and pressure is as expected, I had this on my m6 and on petrol it leaked. Turned out it was a bad fitting on the petrol to engine side of the valve Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF