Does that old law still apply that you can drive a 3W on a motor bike license . Just a thought as it used to apply to the Reliant
No! Until Oct 2000 if you passed a motorbike test, you got B1 automatically. B1 is a cyclecar 550kg or less. Pass a motor bike test now - you don't get this category.
A car licence, group B includes B1. New Morgan is a B1 vehicle.
Note the 550kg weight only applies to the licence needed, and not to the taxation or MOT class. The new trike is a class 4 (car) MOT, but few class 4 MOT stations will have the gear needed, so the new owners are best advised to seek a MOT station that is class 3 (light three wheelers) and class 4.