40 year old cars Need not have an MOT , could be a good thing apart from one vehicle I know as should be welded up My old 1976 1850
Further advice on taxing in the historic vehicle tax class can be found via the
following link: https://www.gov.uk/historic-vehicles
^^From 20 May 2018 most of these vehicles will not need a valid MOT certificate to be used on public roads. You still need to keep the vehicle in a roadworthy condition and can voluntarily have a test. We recommend continued regular maintenance and checks of the vehicle.
In the years I had this car I had some stupid Fails it failed twice on this
1) wind screen washers not hitting wind screen .. the reason for this was Bonnet was open just enough ( sitting on spring ) and the jet of water would not go past the vents .. cure Close bonnet .... red faced MOT Inspector

2 ) Door Mirror fell off .. while on test ... Fail .. What happened was As the car was driven in to garage it had to pass plastic curtains hanging in door way one trapped the mirror and whipped it off ... and that was my fault ?

last front Discs so badly worn I hit one with a hammer and broke a big chunk off car sold !! ... its ok you do not need an MOT now !!
So Now you Do not need an MOT ... what is your most stupid MOT fail