How does this work, not useing camps much before, never looked into it, but looking at the port grimaud campsite yesterday it is half price in September for acsi which is a saving of about £50 on three nights, so got to looking for the card but most were sold out but looked on eBay and some firm called outdoor bits had got some for £13.50 so I have ordered one so am saving £35 on just the three days, never mind any more camps we might use, is it this simple or is there a catch, do you have to register or something after it comes or is it really a no brainer that it looks, if so how's it work.