Spoke to a mate who did the service, and he said the same ... it just takes a while for the oil to circulate, and the noise is the tappets. He has yet to hear anythign majorly wrong with the engine/car.

I guess the cold weather doesnt make the tappeting noise any quieter (aparently it was way below 0 last night, and my car is parked on a drive over night semi-exposed to cross wind).

Come to think of it, I remember an AA bloke saying it takes a while for the oil to reach the top ... would being cold make the oil more dense therefore harder to move ?