Hardstanding Pitches

As hubby and i have today come back from a few days on a Grass Pitch, waterlogged muddy and really bad we do not want to repeat this ever. We have booked two sites in july. Gowerton and Shawesmead. Looking at these sites not all pitches are hard standing. As we are coming quite a  distance , and depending on the weather how do we make sure that we get hardstaning and not grass. do we need to ring the site . Thanks for all your help