I will provide an honest answer. I trust this will be appreciated. Please remember that a low rating PUNISHES me for being honest and that I receive nothing for my time until a positive rating is clicked.
the ccid code you have stands for:
Lighting system! Stop the vehicle carefully
Check displays and possibly turn signals, foglights, main-beam headlights and headlight flasher inoperable.
Stop the vehicle, check and continue journey with care. Have the problem checked by the nearest BMW Service.
you have asked: Do you think this was caused by disconnecting the battery / changing the interior or damaging the headlight button?
it could have been caused by either but more likely the battery if anything. it is likely an internal fault within the footwell module which controls all lighting
And would it be an easy fix or dose it need to be reprogrammed at BMW?
this will not be an easy fix, and auto electrician probably won't be able to do much - I would skip him (save the money) and take the vehicle for proper diagnosis at a BMW garage with the equipment necessary for this (and yes programming would be required if the footwell module is replaced).
be sure to check fuses if you have not, just in case
Please let me know if you have further questions. Please do not forget to click a positive rating as this is the only way I receive credit for my answer, thank you. Best wishes with your vehicle.