My vote would go to Earls Colne - As you mention, both hard and grass runways available, clear of controlled airspace.
I recently completed my PPL there... Good facilities and friendly people. The Robins are very well kept and are a reasonable rate.
All the instructors are fantastic, especially Eddie and Malcolm. Through the summer there are lots of group activities and fly outs if that takes your fancy.
I am now part of a group at Duxford, but will be a regular visitor and should anything go wrong ( ) with the group I am now part of I would gladly rejoin the flying club there and fly with them.