No worries
I've always thought it was an odd choice to put just the one switch in the car, and it's very awkward for a passenger to reach across to unlock the doors if necessary. I preferred the central switch on my older 5 series (E61 and E39). I assume you have to remove the door card to fit a second switch? They look quite pricey too, a quick search suggests around 70 Euros/85 US Dollars. Not sure what a UK dealer would charge...