http://www.keen4parts.co.uk/shop/page/1?sessid=sAUGcSySdsMBlFkf5xWrR16xJCHgYGL9YHdmtYfsLRcP3nrbohpIy9HH4r2Inkps&shop_param=I can highly recomend these kits to anyone. The service over the phone was fantastic and the kits arrived a day earlier than they said too.
The towing electric kit I bought was very easy to install. Just unplug the connector into the light cluster and plug thier plugs into each end to T off the wiring. They even said where to fit the earth wire. All an extremely neet job, very simple instructions and good service.
Only down side is the 12s(plug for caravan wiring like fridges etc) doesnt have a reversing wire in the last section that is sealed to the plug so I had to run my own from the light and use black insulation tape to hide the wire. It does say in the instructions to use extra wire or T off from the 12n kit, but wasnt obvious where to T off from. But even so, still easy to install.