Hogarth1
Manston would not work for many reasons - transport links aren't as good as people need and the amount of flights would not be feasible with current airspace routes from all surrounding airfields and FIRs.
Manston was tried a couple of years ago by an outfit offering flights for a penny etc. They did not last long. RYR would not accept the long detours from route that is needed to give them a safe climb.