The RAF Henley site you are referring to is based just outside Henley near Marsh Lock on the river Thames. It was never a flying station if I am thinking of the right site and was as you say used for producing aircraft engine parts and later on as a Regional Seat of Government (RSG). Both Henley and Warren Row are both owned by the same document archiving company and are in private hands. I’ve been in the bunker in Henley many times but only visited the outside of the site in Warren Row.

The Henley site was predominantly based around it’s bunker which was pretty big. When I visited above ground there was only a medical building, a canteen and the guard house / bunker entrance buildings.

http://www.subbrit.org.uk/rsg/sites/h/henley/

http://www.subbrit.org.uk/rsg/sites/w/warren_row/index.html

I have books with much more info on both sites if you want to contact me, but quite a bit can be found on the web. I also have a plan of the Henley site somewhere.