Thank you. The site connection is not a satellite connection but a normal arial type so I would need presumably a male to male arial lead from the site to my van, an adaptor at the external point of the van, then an adaptor inside the van to plug my TV arial lead to??
I would just expand a little. The best option is to buy a bag of F-type plugs, a bag of TV plugs (technically known as Belling-Lee plugs,) a bag of back-to-back F-type sockets and a length of WF100 cable all from Screwfix or Toolstation. The bags of 10 will cost you about the same as a pack of two from a DIY shed.
Make up long cables with F-type plugs on the end. Sites usually recommend 25m so I made a 15m and a 10m so that I have a cable length option - remember signal gets attenuated by the cable. Doing it this way means that if you ever go satellite you already have the cables.
The sat connector in the battery box should go straight to the sat connector near your TV. You will need to make one short cable F to B-L for the pillar connection and one a bit longer to go from the sat connector inside to the TV. Finally you will need some sort of sleeve to keep water out of the pillar adapter connection.
Note: F-type connections are rated for the full frequency range that satellite requires but Belling-Lee connectors are not, plus F-type give a much more solid connection. The cable for Freeview TV (from aerail or pillar) is the same as that used between a satellite dish and the sat box inside the caravan.
There is lots of info on line how to fit F-type and B-L plugs correctly to the cable. You will ideally need a Stanley knife or similar and a pair of electronics wire cutters.
One last thought: have you checked whether or not you can receive a TV signal directly on your aerial? IMO the comments about poor TV reception in the CMC sites handbook seem to relate to analogue days - digital TV is very different.