Hi Steve,
I appreciate the advice.
My intention would never be to wire aftermarket fitments into an existing loom, but rather check if existing wiring and connectors are in place behind door cards etc, or run my own wiring to the rear glove box fuse deck.
Long coding is my preferred option for changing settings with OBDeleven, and this is to switch on hidden MMI functions, ambient lighting controls, horn with lock etc.etc. and always after backing up existing settings.
I may well take a look at VCDS.
Thanks, Steve