I seem to recall someone on here saying that the Club sites, in particular, were meant be able to save a little space to accommodate late arriving walkers and cyclists even if the sites were officially at full capacity.
That has been the policy of the CCC. Any roadmap to getting back to normal though may well mean that sites open without the facilities blocks being available. That is easy to deal with for caravan and motorhome owners. Those using camper vans without onboard facilities, and tent campers, may well only be accommodated if they arrive with a portapotty and toilet tent...
I suspect that cycle tourers and backpackers may have some further time to wait before we can use campsites
My understanding is that all CCC campsites are generally operated under a franchise arrangement. Their Certificated Site network (i.e. the small capacity ones that can operate without having to have obtained planning permission to be a campsite) are all privately owned. Not all have facilities (essentially a loo) to accept tent campers.