DaveW: Thank you very much for your response.
Yes, the gearbox is the Ford one with a pretty standard looking drain plug with a flush Allen Key fitting. I guess the only way to find out about the type of seal is to unscrew it as you suggest - and drop the oil.
The plug seems tight when checked with an Allen Key - in fact the old paint line up markings to show no movement are in line - but if the seal is shot or there is grit in there somewhere then I'm sure oil will seep through.
It wasn't leaking before the dealer did the oil change which is why my major suspicion is the washer/seal on the drain plug.
Am I correct in thinking that when you say the Ford Plug has an Integral Seal the only way to replace it would be with a complete new Plug?
