Your best shot is to contact by phone or online email www.towingandtrailers.co.uk
tell them what you want to do I suggest using the pre-wired S & N sockets Pt No. PE 02 Pre wired N and S type electric sockets £11.99 fix to caravan tow frame to plug in the short trailing leads then wire up the S & N plugs the other ends after cutting to right tow length. then ask for the two plugs S and N ie one for road lights the other for caravan auxiliary
only £11.99
Just what you need but you may not like it the way I suggest. Pre-wired sockets with grey and black wires only needing the plugs to be added to the other ends of cables ask for wiring diagram or search net.
Bob
September 2010