Blue G48 is recommended. I just bought mine from BMW dealer. With BMWCC discount it was only a couple of pounds more than Comma.
Red anti freeze could be used and will protect against freezing, however, the anti corrosion protection will not be as good.
Never mix red and blue types, they are incompatible and apparently turn to a gel.
There is a good explanation about the different types of anti freeze on the Opie oils site.