Pretty sure they dont have a fixed structure, weve been offered different rates for different times of day in the past. They take county cards too if you have one. Best bet is to pick the phone up to them (obviously not so easy today/tomorrow now)
Edit: Appears they are on tee off times currently for between £20 and £30
From their website "The green fee varies according to the day and time you wish to play and it is best to check prices and availability with the pro shop before travelling. (Tel: 01608 730047)."