Historic vehicle (>40y), doesn't need MOT. Age refers to building date, not first registration.
On one hand the Dept for Transport says:
Eligibility
You do not need to get an MOT if the vehicle was first registered more than 40 years ago and no ‘substantial changes’ have been made to the vehicle in the last 30 years.
but elsewhere it says Most vehicles manufactured or first registered.
Confusing. I always understood the first was the case. A colleague had a Capri manufactured 41 years previous but first registered 39 years previous and he was refused MOT exemption.