As i happens i had an interesting arguement with my MOT tester last week...
They failed my A4 for having a non-functional Engine management light.
It doesnt have one. Theres a bulb position on the dashboard, but A4's built before 2001 simply didnt have it connected in the European market. No idea why, but they're all like that and theres not even any wiring between the cluster and ECU. Many pre-2001 VAG models are similar.
However they've recently added the check for a working EML to the MOT, and the test has no provision for saying "it doesnt have one". It simply assumes all cars have one and that it will work.
He phoned VOSA, who just sorta shrugged and said "we've seen it before with a VW but not an Audi". He then phoned Audi, who insisted the car should have a management light (clearly main dealers with no clue about >18year old models!).
In the end i ended up printing out the wiring diagram for my car, and also for a 2001 model, which clearly showed the 2001 car had the bulb and wiring shown, and my car had nothing which was enough to satisfy him and he passed it. But your average joe isnt going to have that sort of info available to convince the tester, clearly these changes havent been fully considered!