Originally Posted by tee-rex

Sorry fella's your all wrong if you present a car for an mot and it fails even with 4 months test still to run you loose any unused time and the car can only be driven away to a place of repair.
Its a myth that you can test a car early and if it fails carry on driving on the old test certificate, every test carried out will generate a new test number and all old test numbers are then obsolete.
however if you test a car with 30 days or less still to run and the car passes the extra days will be added on automatically.
Quite a few people fall into this trap as they still have the old certificate but it shows on dvla the car has no mot, The only way round it is to ask the mot station for a pre mot and not to generate any paperwork via the mot computer this way the test is still valid to the expiry date.