Buy your food when you get there, extra cool bags, bottles etc take loads of space. We also couldn't manage without our roof box. Definitely worth getting. Our kids are out of Car seats so they sit on blankets /duvets. We have also used vacuum bags for clothes & bedding as the pump we have for the air beds also sucks the air - hey presto!
Hadn't thought about that so I will investigate, thanks. They are young teens so fairly large. It's literally one blanket or duvet, they aren't like the princess and pea with multiple layers so could this still be an issue I wonder?
*Cut down on clothes, many sites have a washing machine which you can use halfway through.
*Get your food shop delivered or use click and collect.
*Try to use squashable items where possible- the ikea blue bags or supermarket bags for life are perfect for clothes and a lot of other things.
*If you do want to take and use plastic boxes for storage when there, place each box inside each other and fill just the one box, remembering to pack the lids, or stack these on top, When you get to the site you can unstack them and use in the tent but they have only taken the space of 1 in the car.
*Use every last bit of space, you might get a tin/gas canister in the nesting cooking pans, roll teatowels etc into spaces.
*We've just got some hamman towels, I am amazed how much smaller (and lighter) they are. 3 bathsheet sized towels take the space of a normal one.