I ask as the document that had been sent (NTK) had all of the terms it says not to use.
The source www.britishparking.co.uk/AOS-Code-Changes-2018
scroll down the page to the section Re: amendments
The idea was basically that if they were not supposed to use these specific terms in a notice the POPLA would see that hey had indeed used all of them and . . . .
I can't quite remember where we are on this. They now say that it needs a full gearbox whereas in the letter I suggested that they can have an opportunity to repair. However, I understand from you that you don't want to deal with them any more – and I think you're right. Also, a good new gearbox means that the car is so fundamentally not of satisfactory quality that you are entitled to treat the contract is terminated. On that basis, it might be better simply to say that you are treating the contract is terminated and that you want your money back.
How does that sound?
Also I'm wondering how to communicate the news to the finance company.