Just had a price from Cardiff Audi to retrofit cruise control to the old girl.
Now there was a time when VW, Audi etc were doing this for £150 - £200.
Here's the email I got
Haven spoken to the parts department they have given me a price of £560.16 that is all inclusive of labour parts and VAT. We would need to see the vehicle first to order the specific parts to your vehicle. If you would like this to be carried out please let me know when would be convenient.