ENVSM has supplied the below file which explains about the accommodation and camping options on site. There is also a booking form.
Unfortunately due to another event running until Saturday 22 July, booking a room on site may not be possible until Sunday 23 July. After that date there is no problem, so this means finding somewhere else locally for a few nights depending on when you arrive. There are two campsites within a 5 minte walk as well as other options. Further details in the document.
Dowload the details and booking form here.