Single parent group Gingerbread have published a factsheet containing their tops tips for surviving Christmas. Sensible advice for parents, even if not separated. Their website contains lots of other useful resources, for example this factsheet on child support.
Remembering Mr Banks
I know some would say I have a tendency to overshare, but I'm afraid it's hardwired, so look away now if that sort of...

do they advise separation as a way to survive christmas?
arf
I think adults should be allowed to hibernate for the festive period and emerge at some point in mid January!