In some cases a jeep pulling a horse box is legal on an ordinary b licence, problem arises if you put a couple of horses in the bloody box, the horses will put you over the gross vehicle capacity for a b licence. Weight of jeep 2500kg box 800kg if the horse is over 200kg your overweight. You will need a "eb" licence for this. Where you will then work off the gross vehicle weight of the jeep which will be in or around 6/7 tonne depending on the jeep. (Car/van etc )