Baz, as others have said, we are all individuals and Wg treats us as such.
The one tip i can offer you is to try and work in periods and take regular long rest breaks. (ie. work two hours, rest 30-45 mins etc.) Impracticable I know but it was the only way I managed my job initially. it was that or go off sick, so I decided that some work was better than none. In your trades though, the customers may not be so accommodating as my bosses were.
Be nice to your kids, they will choose your nursing home.