Update (and hopefully closure of the topic!):
The car has been inspected by the dealer and no mechanical issues have been found. The gearbox oil has been changed for the Ford recommended WSD M2C200-c spec. There does not appear to be any noticeable change in drive train noise (to date) but I am happier knowing that there are no mechanical issues and that the recommended oil is now in the box.
Just need some good weather now to take it for a spin
My thanks to you all for your advice and help - it has been an education!
