As standard the caravan will have the twin 12n/12s plugs so you can get 12n/12s sockets fitted to your car or just the one 12n if you are not bothered about fridge & battery charging while you drive.
The newer 13pin plug was fitted as standard to caravans around 2009 onwards, I think. It is also possible that your caravan has been upgraded with a 13pin plug & these can easily be fitted so worth a check to see, or have one fitted & then have a 13pin socket fitted to your car because it is a better system.
If car & caravan have incompatable plugs/sockets, adaptors are available for all situations but can be a bit cumbersome.
Ok , so if I understand this correctly if I had the 12s socket fitted and also had the 13 pin socket fitted , when I get there to collect the caravan one of these should work ??
No you don't have to do that. For a single socket its a 12n, the 12s is the extra socket for caravan fridge & battery. Your cheapest option would be single 12n socket fitted to car & take a 7pin socket to 13pin plug adaptor(a few quid from Halfords etc). This would allow for any eventuality, but its most likely caravan will still have its original 12n/12s plugs.
A 12n on car & the adaptor as described kept in your glovebox will allow you to tow anything at anytime for roadlights to work ok.