If you're sensible there's always a chance to build in a break into the day.
Get the first service done. Clear up. Assign rest to 2/3 crew and close off a galley to rest. Have two crew on hand to assist passengers. Then once the time is up, swap over.
Yes, as crew you're always 'on duty', but it's no different to an office worker taking a break knowing the phone could go at any time.
Or, we could increase turnaround times by 20 minutes, and push up prices or reduce ROCE on each aircraft and risk jobs or bases?
I don't believe for one minute that on the long sectors TCX do that there can't be time found for 20 minutes of rest.
Perhaps the pursers could be taught better time management?