It all depends when you passed your test (as opposed to what your current licensse issue says) amongst other things- there are "grandfather rights" for those of us who didn't need to do the current trailer test originally for towing "big" stuff, otherwise you're same as anyone else who would sit their test now. I forget the cut- off date.
One thing to watch is that if your "train" is 4.1 tonnes, you may be illegal as I THINK the B / BE is for 3.5T GTW. I used to be legal to drive 7.5tonnes (and did), but lost that 3 or 4 re-issues ago......
There's a few pages on the DVLA website if you can get your head round the legal speak.