I visited Great Oakley yesterday.
It's a well kept and friendly place. I had some problems with my PPR - couldn't get an answer on the telephone, so called on the radio 40 mins before my (hoped for) arrival and got permission over the air. He does say on the web site though that permission should be obtained by telephone. The website: http://greatoakleyairfield.co.uk/
has all of the details you'll need.
Upon paying the landing fee, Tim (the owner) made tea/coffee for both me and my passenger. He told us about his plans for the place. He's pretty much finished a kitchen and food will soon be served. It looked very good.
The runways are immaculate and well marked. It wasn't hard to spot from the air. I'll be going back sometime.