Phill, as you will know that is a French car and I believe the German authorities also allow this no matter the age of the (Morgan) vehicle as the trailed item also has to have an MOT.
I don't understand the logic either.
Here there is an age limit, ironically after a certain age (I don't know the cut off) Morgan's were no longer allowed to fit a tow bar.
A great shame for people that enjoy this kind of touring whilst having a great car for unhindered exploring, I know Tim has an earlier car hence my comment.
There's no way I'd pull even a micro caravan with a Morgan, the weight of the trailer would be far too close to the weight of the car. Those Go-Pod caravans weigh 500Kg empty, and you need an MTPLM of 750Kg to be able to legally tow. My car weighs 850Kg wet. Although my car is old enough not to need to comply with the later rules, they were brought in with a very good reason, and I'm by no means certain you could get insurance cover anyway.