Many thanks, Richard, George and Rob. Yes I was sceptical re the BPS and in another sense I am still so.
George that is a very helpful information. So „normally closed“ when not operated is the right switch for both, Brake Light and BPS because it is all the time operated by the brake pedal (pushed in) to stay open when not braking.
I will check which item Melvyn Rutter has on offer to replace the BPS because I need the NC version anyway.