It is a lot easier here in Queensland Oz. The Triumph club gives you a deceleration that you are a club member, & your car is historic. You present that to a motor registry office, or in small towns,[6700 people like mine], to the government office, & you receive CLUB registration. Costs A$250 including third party insurance against A$750.
The car is only supposed to be used for club activities, or driving to get service. The triumph club has reciprocal invitations with about 50 other clubs, so you would be very busy attending everything. Besides I have a Triumph Tragic mate in town with a workshop I usually visit when in town.
Some complain it is a lot of trouble here, I don't think they would like yours.
Hasbeen