Check CASR's
It has been a while but I remember something in CASR that permits an AOC holder to operate into a destination with one category less ARFF. The ARFF category normally required is decreed by the aircraft size (pax, length etc) and those requirements are specified in CASR 139h. Cannot remember if the one category less exemption is in that CASR or the AOC licencing CASR. I will leave it to you to check.