Thanks for the update and appreciation. Here's a brand new circuit board that your local T4 can programme to your car:
https://www.ebay.co.uk/itm/GENUINE-R...gAAOSwrTFdWnLh
A bit pricy but much less than your original quote.
If memory serves me correctly there are five positions or slots for the remote locking function, two have already been used, which leaves you with three vacant ones.
Good luck
Mike