Mate, any modern car is tested from the sahara to the artic circle.
I really wouldn't worry about the cold doing any harm in the UK. Turbos run at near 1000 degC, so starting from a 20 degress less makes no odds to the operating range.
-30 is a walk in the park for a modern car, if you've ever been to scandinavia you'll know they have plug in points on their driveways to hook up the car at night to power a small water heater/pump in the engine to keep it cosy.
But thats for -40 ish, where your eye lids freeze & summer tyres crack and burst......not quite London