Heidi, I’m sorry if you feel I was trying to shut you down. My reading of your post led me to believe you hadn’t read through what had been discussed before, and it didn’t seem you were bringing anything new to the argument.
As I understand it there are two issues. If a dealer takes an order from a private buyer and an order from a Motability scheme user, and then prioritises the private buyer in any way, that is clearly discrimination. If you have evidence of that you can act. If the dealer or manufacturer chooses not to supply cars to the scheme, that’s a commercial decision and perfectly within his right. Disability is only one of the protected characteristics in law. Parents with small children are also included in the definition. It can’t be the case that car manufacturers or dealers should be required to give them some sort of priority when selling new cars.