From memory C1 only lets you tow 750KG as well, need to do a separate trailer licence regardless.
it's a little more involved than that, you can tow a lot bigger than that depending on the gross train weight, and rules are slacker for even newer drivers!!! before 1997, you don't need a seperate trailer license and can tow a trailer upto 3500kgs with a MAM of 8.25 tons after 1997 you can have a MAM of upto 3500kgs, so, if your car weighs 1 ton, and is legally allowed to do so (unlikely I know but just for illustration) you could tow a trailer of 2.5tons. the license for towing trailers upto 3500kgs is B+E
this explains it all fairly clearly
https://www.gov.uk/towing-with-car
with regards to vehicle weights
a cat B licence only allows you to drive upto 3500kgs. People who passed their test before 1997 will have category C1 on their license allowing them to drive upto 7500kgs.
a clear explanation of this can be found here
https://www.gov.uk/driving-licence-categories
One anomally worth noting is this.
Lets say you have a catB license and you want to pull an empty car trailer, are you allowed to do it? The answer is,no, because the governing factor is the plated weight of the trailer, not the weight it actually carries.
So, what about if I want to tow a 3.5ton plated trailer loaded to a total weight of 2.5 tons behind my hilux, which is plated to tow 2.8 tons?
The answer is yes. Here is a copy of an email I received from a technical officer at VOSA. If anyone needs the original contact details as evidence if they have a problem, let me know. Not all police or vehicle inspectors understand the regulations!!
Andrew
I refer to your mail of 7 February to VOSA Enquiries with the above title.
I confirm that for technical purposes a motor vehicle can tow any trailer provided the towing vehicle's towing capacity or Gross Train Weight is not exceeded, regardless of the Gross Vehicle Weight of the Trailer. Thus your example Hilux with a 2.5 tonne towing capacity can legally tow a trailer laden to 2 tonnes even though the trailer GVW is 3 tonnes.
The only regulations that make usage limitations based on trailer GVW rather than actual weight are some categories of driving licence, tachograph and driver's hours, and goods vehicle operator licensing. Those that govern overloading offences, the Authorised Weight Regulations 1998 and the Road Vehicles (Construction and Use) Regulations 1986 do not.