after a bit more info from customer, it turns out its not had a service or oil change for 16000 miles, this is after he has just spent £400+ at another garage trying to sort out cold start issue, so i flushed it and changed oil and stuck a fuel cleaner in tank and also the other garage had fitted new injector to no4 cyl but had not coded it in so ive done all that and its fingers crossed for the morning