Auto Zone And Advance Auto part both have trailer sections where you can get almost any connector or adapter you might need. Since I haven't gotten my Discovery on te road yet, I haven't done this, but for my Ford wagon, I got an adapter box that connects to the lights and power in the car. It uses the lights just as control lines, so they're isolated from the trailer, and the output of the box is current limited so that if anything shorts out on the trailer, the vehicle lights and power are unaffected.

Since towing is one of the reasons I bought it, I'll be adding this to the Discovery in the next few weeks.

 

Anyone try this?:
Trailer Connector - 7-Way European Round To Flat-4 Conversion Plug / Harness - Land Rover trailer wiring kits & harnesses from Atlantic British
For a Disco 2 that is.
I'm skeptical of it's simplicity.

Got this today, definitely not useful.
7-Way Round Pin to 4-Flat Adapter Tow Ready Wiring 118709