Update. Brought it in to the dealers today and they've diagnosed it as a failing water pump. The sound was very evident this morning thankfully. As per previous post, no loss of power and temperature was stable and no signs of overheating. Just a whirring noise.
Seeing that the car is barely used and such low mileage, I'm shocked by this. In my previous 147, I only had to change the water pump after 80,000 km!! Oh well, at least the turbo is intact but it this 1750 Tbi engine is slowly sapping my confidence and trust in the marque.