We'd better bring our own fire truck instead of one extinguisher. Can we fill up de pool with or own water too.
I think the allocation of the piches by size is still the best way to go. I think they should make a more detailed grid map of it up front to calculate size on location by visual references en adding up grids. Shouldn't be too difficult. You just have to make the grid map once and you can use it every year. Just as a reference for the campsite guys to make it a little bit more doable.
And it would be easier for the ACO to make a group ticket buying option. You say how big a pitch you want and they give you a map on which you can indicate the location with a marker. Send it to them, they can easily check the price vs size, send back a confirmation of your spot and price, you pay and before arrival all the group tickets are already market on the fields. Groups happy with having some pressure off for getting their spot. ACO happy because there is no way anyone can argue about their groups spot size and location.