BIG TUDOR,
Scheduling Agreements are 'company specific' and are usually forced into place by employees when companies flaunt CAP371. CAP371 is a 'guide' to the avoidance of fatigue in aircrew and like most official docs, it could be open to misinterpretation........ There will be smaller airlines that work with CAP371 alone and that would be sufficient. It wouldn't surprise me that agreements would have to be cleared through the CAA as a precautionary measure.