Sad.

We cant help you. And it sounds like you know so little about it that you cannot even determine if the shop is qualified to work on it.

Very very few 'auto electric' or 'car repair shops' will have the skill to re-configure a BMW to activate a feature that was available as a facotry option. You need to determine if the base wiring harness is there; add what is missing; then code the electronics to activate the feature. 500GBP is reasonable for that effort. (on top of the wheel cost)