Bmw no longer using Castrol Edge 0W-30

[E65Ross]

Hi there, I remember my old man saying that BMW no longer stock 0w-30 Castrol Edge at his dealer and now use total quartz 5w-30, does anyone know which one they use? I wonder why they've decided to stop, and why the move from 0W-30 to 5W-30. I prefer the idea of a 0W because it's thinner for cold starts, but I guess it's really splitting hairs here in the UK.

Cheers