also interested in this answer. as an fyi i asked my local dealer this same question. they advised a new MBB is £499.50 ex VAT. In regards to programming they werent sure. they advised they would first need to open a case as an issue and then send it back to zero to see what they say. this would start an hours worth of labour to open the case and then whatever cost zero decide to charge
So I found out some more info by digging through the unofficial manual.
The more recent bikes (?2016+) have a newer version of the MBB with more memory. This allows firmware updates by app, whereas the older bikes/MBB can only be flashed by the dealer.
The reasoning is that the newer MBB have sufficient flash memory to store the existing firmware AND the update such that in the case the update fails or is corrupted, you don't end up with a bricked MBB.
I was quoted £460-odd ex VAT for MBB including shipping it to Zero EU for programming. Potentially the newer one is more money? There's only really one dealer in UK. The place which sells them in Jersey where I am have the software but are unwilling to do any service as nobody is trained to use it. My bike is dead, I'm not shipping it to Norfolk, so my only option is to gamble on replacement MBB.