That helps alot! Also found this to help
Enter the details of the towing vehicle and trailer in boxes X, Y and Z (you will find these details in your vehicle manufactures handbook and on the trailer manufactures weight plate which is usually riveted to the 'A' frame near the towing hitch)
X
Unladen kerbweight of towing vehicle
---------------------------- KG
Y
MAM weight of towing vehicle
---------------------------- KG
You may tow a trailer on a category 'B' car driving licence if the calculator above has shown the following:
If 'Z' is weighted at or below 750 KG 'Y' + 'Z' does not go above 4250 KG
or
If 'Z' is weighted above 750 KG but that weight is less than 'X' and therefore 'Y' + 'Z' is equal to or less than 3500 KG
You will need to take a test and gain the B + E entitlement for your driving licence if the above calculator has shown the following:
If 'Z' is weighted at more than 'X' or
If 'Y' + 'Z' is more than 3500 KG
Once you have the B+E on your licence it does not matter if the MAM of the trailer is higher than the towing vehicle as long as you do not load the trailer to more than the towing capacity of the towing vehicle.
Z
MAM weight of trailer
---------------------------- KG