Fume Event,
What Cessnapete says above is ABSOLUTELY true, and you know it.
One example (of many):
In the disruption earlier this year, with dozens of LHR inbounds diverted to other UK stations due snow, BASSA insisted that many of the cabin crews take two local nights rest at the diversion station, before continuing to LHR.
This was an industrial rule, not the law, and BASSA insisted that it was adhered to.
So when you say "The only restriction would be if the cabin crew did not achieve sufficient break time to continue ie at least three hours horizontal rest." you are wrong.
I am confident that you will not admit or acknowledge this.
Prove me wrong.