I just found this thread & quite frankly, the last comment made me feel unwell and worried I had made big mistake, as I have just bought a caravan and new tow car to match & I passed my test in 1997!! However, I had looked into this very carefully before my purchases, and also taken a towing course (with a caravan). I checked out the Government Highways Website and many other info sites (caravan club etc), and no where do they mention braked or unbraked being a problem. This is an easy way to understand the rules as found on Caravan Club Website & Gov.org.uk: Cat B vehicles may be coupled with: * a caravan up to 750KG MTPLM (allowing combined weight up to 4,250 KG GTW) or* a caravan over 750KG MTPLM provided the MTPLM of the caravan does not exceed the unladen weight of the car. And the total outfit (car+caravan) does not exceed 3,500KG. However novice towers are advised by law not to exceed the 85% rule (total MTPLM of caravan must be no more than 85% of the kerb weight of the tow car).
I also checked with the tow course instructor and White Arches of Rushden that my licence is valid, as I strongly agree, it is all very CONFUSING.