Safeskys still advertising a vacancy at North Denes. It says APC as well as ADI, but they might take you with just ADI. They have been known to send people from North Denes on APC courses.
Edit:
Just discovered Safeskys have vacancies also for 'an island off the UK mainland', looking for SATCO and ATCOs preferably with ADI/APP/OJTI/Met Obs. same as at North Denes
SafeSkys Air Traffic Control Services, Air Traffic Control Engineering, Bird Control & Wildlife Management