A good point with the driving license, and one which will impact more and more people as time goes on (and could likely start to affect the resale value of caravans as the potential user base reduces year on year)
I am pretty sure a towing endorsement is not needed as long as the total train weight (vehicle + trailer) does not exceed 3.5t
AND the trailer is under 750kg (that is to do with the need to have brakes on a trailer over that weight and a endorsement needed for a braked trailer).
There must be very few (if any?) normal caravans under 750kg, but I would think there will be a fair number of Folding Caravans and Trailer Tents that would fit the weight bill for a Driver with just a basic B Car License who fancies taking their accomodation behind them - but for those folk, a Motor Caravan of some type probably makes more sense for an easier life.
In my own case I am decrepit enough to have both a C1+E and a B+E Endorsement on my license automatically so am covered for any of these options