Thanks Mark,
Since this is the first time you have had to add ( probably about 1 litre) in 13.5 K miles from new, then I would say there is nothing abnormal about that. You will probably find that this consumption decreases at the next oil change. Of course if you find it needs more frequent topping up, then you will need that investigated at that time.
It is clear from what you say, that the car is indeed on a Longlife service schedule which normally means around 18k or 18 months - whichever comes first - between services.
Kind regards,
Gareth.