The battery problem has been solved on my 335 Tim
The Techie came out from the BMW breakdown service and plugged his Laptop into the car - It showed that each of the stepper motors on the heating and vent system, there are seven motors, each had 61 faults, and some other bit od witchcraft had 62 faults.
He unplugged the main fan and booked me in at the local dealer an arranged a hire car.
He showed me a "PUMA" BMW speak for documented faults and fixes, which showed chaffed wires. This was the fault and it required partial dashboard and loom removal, then re insulating an re routing.
Apparently four to six hours work - Ive got the warranty plan so only my £250 excess to pay.
They loaned me via Enterprise a well specced 320 D so this years policy has paid dividends.