As a part of our DTO paperwork, we decided as a Club to define supervision in this case as the supervisor being on site, if flying then only in the circuit. We knew we didn't have to do this, but it's what we wanted to do. Our most recent FI(R) had a supervisor on site at all times (but giving him plenty of elbow-room) and has now thankfully had the restriction removed, so I can now take occasional Sundays off!
TOO