I'd expect it to be like when the Passport Office was on a strike/go slow. Passports were extended, I think at main Post Offices if I remember correctly. Then you just applied, and got a 10 year when the dispute was resolved. Otherwise you'd be paying full price for possibly a 6 month MOT. Mind you, garage owners would rather have it that way as they'll be seriously losing out, especially those that specialise in MOT's.