Apparently these are the people to talk to about towing questions, in the UK:
Vehicle Standards Engineering
(5) division
Department for Transport
Zone 2/01
Great Minster House
76 Marsham Street
London
SW1P 4DR
The telephone number is 020 7944 2064

As for the driving licence thing, 1st Jan 1997 was when things got tighter. Licences passed befor that can tow what they like up to the trailer and tow vehicles recomended maximum, as long as the total weight is less than 8.25 Tonne.
After 1997 it's: Trailer up to 750kg (allowing a combined weight up to 4.25 tonnes), OR a trailer over 750kg provided the weight of the trailer does not exceed the unladen weight of the towing vehicle, and the combination does not exceed 3.5 tonnes.

Found this site, and thought of this question: http://www.ntta.co.uk/law/law/identification_plates.htm

A car being towed on a rope has to be road legal, inc. a licenced driver. There is much argument as to whether a car being towed on an 'A fram' should also be road legal. I have towed many non road legel cars this way, but only ones that look like they may be 'safe'.
As for trailers. There is no 'MOT'. There have been rumers of one being brought in, in the future, as in many continental countries. There are laws that apply though. One's I know are:
1) Lights. Tail, number plate, stop and indicaters as aminimum. All in working order, and showing no white light.
2) A number plate that matches the tow vehicle.
3) If it's over a sertain wheight (750Kg I think) breakes opperated by the trailer pushing against a slowing tow vehicle.
4) If it has breaks, a hand opperated break, and an emergency break cord/chain which will opperate the breaks, and hold them on if the trailer parts company whith the tow car.
As you are a student I asum you have not had a licence long? If not, I can't remember when the law changed but people who past their tests after a certain date have to take a seperat test to be able to tow a trailer on the road.