This is an update I should have done a couple of months ago, I put a one way valve in the fuel line and that made no difference, then I changed the weep pipes as one of them looked a bit wet and bingo the car is back to normal again but in the mean time we bought a new car so no longer have the zafira, but I know the guy who has the car and he did nearly 600 miles last weekend and he said it never missed a beat.