A number of years ago when I had the 900 hr pa problem and wanted to fly my aircraft on days off or when not on duty, I sought and received a concession to exceed the weekly, monthly and yearly limits by 3hrs, 5hrs, and 50hrs respectively. The only limitation was that it was limited to “recreational flying in VMC” . The company and Chief Pilot were informed and did not have a problem so long as the flying was marked as ‘private’ in the log book.
The same concession was obtained by a number of other pilots in the same company and the wording was the same.
The argument that I used was along the lines that the CAO did not have the right to deny a licence holder of partaking in his chosen recreational activity – in my case flying at times when not required for duty – ie days off or after work. There were a lot of other activities that would cause far greater fatigue than flying a GA aircraft.
It’s a bit akin to telling a truck drive he can’t race his sports car on the weekend….!
I don’t know what the CASA policy is now, but if you have a problem that can’t be solved by arrangement with your company then seeking a concession is the next option.