The US hitch is 2 inches - UK is 50 mm, electrics will have to be changed - US model runs off 110 volts input, as you know UK is 240 volts. Think the braking system is different too . The maximum length you can tow with a non commercial vehicle is 7 metres (excluding drawbar and coupling), width 2.3 metres. This link gives you the legal details for towing:
NTTA Guide to Safe & Legal Towing
Good luck