Managed to get back out on it today (had a weekend away MCN live) all 8 of the injectors were coated in dirt, all now cleaned, still was a little lumpy, I've changed the plugs again to be sure there was no duff one's and was horrified, I knew Pete mentioned the car had new plugs, leads and coils all which is evident (almost!) while changing the plugs I found 2 brand new leads which had been damaged the repaired (badly) and replaced and 2 leads which look to be original lexus leads... I'm guessing Pete you had the car back to the converting garage to do the work as the LPG reg is situated in such a way the plug change couldn't of happened with the reg being moved, going to fit 2 new injectors later in the week which should hopefully cure the issue