The Historic Vehicle taxation class is a ‘rolling’ system, meaning that a vehicle that’s 40 or more years old can be reclassified as ‘historic’ and eligible for free car tax (VED). The rolling system updates occur each April. For example, April 2019 saw all vehicles built prior to 1 January, 1979, become eligible for Historic Vehicle car tax. For your car to qualify, you'll need to prove it was built before 1 January, 1979. The build records for MG are held by the British Motor Museum at Gaydon, so you'll need to purchase a heritage certificate (www.britishmotormuseum.co.uk/archive/heritage-cert...s) - this will show the production data, original colour and options.