Cap 371
A reminder and for Ian to take into account. History of CAP 371. After many, many consultations with all interested parties and Aero Medical specialists in the early 70s (the so called Bader Committee) CAP 371 was acted into law.
Most carriers had/have an industrial document which conforms to, or betters CAP 371.
I remember going from a UK non-sched carrier who's industrial doc bettered CAP 371 to a US FAA121 supplemental (non scheduled) operator where you could operate an outbound 121 duty up to 12 hours wheels off to wheels on, and then a back-end FAA91 ferry for 12 hours. A duty day of 30+ hours. Only time aloft was counted, NOT DUTY TIME!
CAP 371 got it right, don't blow it away, no other regulatory authority has had the courage to go for it, just look at the mess in the US with the FAA, NTSB, NASA, AALP, NATA et al, trying to make a code, let alone those oiks in EASA!!!