He has residency? but nothing legal in place? I would still say he doesn't have a leg to stand on, although I am no expert in these matters, just trying to look at it from a logical point of view. It is nasty of him to use the Children as pawns here. I feel that whatever happens between adults their main concern should be( In a perfect world), to keep everything as seemingly normal as possible for the Children's sake.
I guess your D does need some proper legal advice to be able to move on. I wonder if there is any financial help available anywhere for this, might be worth looking into, could perhaps make CAB the first port of call, or a Childrens charity, just for advice. what a worry it must be for all of you. I hope it goes as well as it can do, keep us posted
Frank Field, Labour Peer has died, aged 81y.