Well despite cleaning all mating surfaces and running the engine for 10 mins after fitting the new gasket with no sign of any leak, I find after driving 10 miles and sitting waiting for a mate, he comes out of his house and says you've got a puddle of oil under your truck, bollox the feckin rocker cover is now dripping, cursed lots and checked the oil, halfway between max and min, cursed lots and then drove home slowly watchin the oil light ready to switch off rapido, then cursed some more and then went to the pub, I will look at it tomorrow, I was gonna have a lie in as I don't have to start work til 10 tomorrow, so that's fecked the lie in!