Another option worth considering for people with an electric heater that simply can't be fixed - instead of the faff of dismantling and remantling the entire dashboard to install it, an alternative to consider (as I did when my BHC did not have working electric heat for 4 years until the week before Christmas because it was in code 00005!) is fitting a DEFA /Calix or similar coolant heater. This is plumbed into the return pipe of the paired pipes that run to / from the oil / coolant heat exchanger, with a socket that is screwed into the plastic bulkhead behind the service panel adjacent to where the panel latch is situated. A cable with a custom outdoor connector runs to this, plugged at the other end into a mains timer switch in the garage. It took my local mechanic under an hour to fit this, and a decent chunk of that hour was fannying around finding the best location to put the socket. Mine is set to run from 0600 to 0845, and has the coolant sitting at a pleasant 54-55˚C as I leave the house (from colour DIS) - so this in conjunction with the electric heater gives proper hot air more or less on departure. Amusingly the coolant is still only around 70˚ on arrival at work 10 minutes later.
