Update - I have just chatted with a BMW genius who says that the electric towbar is indeed available for the 330e.
BUT it is not available to retrofit to new 330e models delivered from 1 September 2019 through to early October. Apparently they have increased the car's battery capacity to compensate for the 750kg towing capacity.
Needless to say that I am not happy at all - penalised for being a loyal BMW customer and ordering a new model early!
