prebooking standard hardstandings

I don't understand why I am not able to prebook a standard HARDSTANDING (been told that they are on a first come basis).  We recently had a 10 night stay at a C Club site and were embarrassed, despite lifting the groundsheet, that the grass had been quite badly affected as the site was one of the best we had stayed at.  The C & C Club and private sites allow prebooking and we have noticed that more are being installed indicating that they are in demand.  we would be happy to pay a deposit.  What do others think?