Smuj .. declassification not needed on a lot of them .. Pembury, Pendine and Staunton all used for "beach training".... as well as publicity ... Top Gear a few years back had a 70 Sqn Herc landing to "so say" deliver a Jag for a test ... aircraft actually arrived empty, Jag drives on, aircraft taxies forward to a fresh bit of sand ... Jag drives off .... 'twas a good day out for all involved ..
You tube has a few clips of beach work .. here's just one ..
https://www.youtube.com/watch?v=5uzpDy3n3Vs
bit of searching ...the top gear programme I refered to
http://www.topgear.com/uk/videos/sand-blast-2-part1
from minute 7 onwards