My worry on this is not the "classics" such as the 500, but the vehicles that will soon be eligible, some people will exploit it.
Here in France, the CT(MOT) is every two years. Vehicles over 30 years old can be registered as "collection", at which point they only require a CT every five years. Registering as "collection" is non-reversible and brings with it some restrictions, mainly insurance related (restricted kilometerage, no commuting or buisness use), it also leaves you at the mercy of the government should they change the rules (previous rules restricted vheicles to their home and neighbouring departments only, unless attending a show, weekends and bank holidays only).
While these rules are fairly sensible, the are being exploited, in particular by the "young traveller" community (young people 18-25 who work seasonal jobs while living in camper vans), 30 years isn't very old when it comes to vans/trucks like the Mercedes 308, Iveco Daily, Ford Transit etc, some of these are looking pretty ropey 4 years after their last CT.
Personally, all my vehicles are registered as "normal", even those over 30 years old, if the rules were the same as the new UK ones, I think I'd go for a check every couple of years, depending on use.
As already said, two pairs of eyes are better.