Back in the 1990s the medical evidence submitted to the CAA recommended limiting CAP 371Table A Flight Duty Period Limits to something like 9 hours for 4 sectors. Especially early morning duties.
In the debate this was dismissed on economic grounds by the CAA committee and this I fear is the problem. The medical evidence will always be dismissed on economic grounds.
Ask the CAA for a copy of the submissions from interested parties ie employers ,unions and medics along with the minutes of the meetings conducted before the revised edition of CAP 371 at or around 1990.
I bet you won't get very far.
The NASA report into duty limits would also be a good read.
Good luck with your investigation.
Most people believe flight crew and I include the cabin crew are under worked over paid and lazy.
To maintain our professional standards we have to spend many hour learning and revising procedures from our Flight Manuals in our own time. Cabin Crew face a check on their saftey knowledge at pre departure brief.
Most crew have to report between 15 and 20 minutes early to complete their preflight duties in time for an on time departure. Parking at work and lack of public transport can increase the need to plan arriving at the car park even earlier.
At one time there was a despatch service now it's all self help to prepare your own brief and flight plan material. Great if it works but if computer says NO an absolute nightmare as you try to brief for you flights.