Thank you for your question
My name is Clare
I shall do my bets to help you but I need some further information first
How much is the house worth and how much is outstanding on the mortgage?
What income do they each actually have?
How much does a cheaper two bedroom property in the same school area cost to buy?
No worries - you will always be able to find us!
Has K made any financial or other contributions to improvements to the property?
Did G ever promise K a share of the house ?
The problem that G has is that under Schedule 1 of the Children Act he is under a duty to help house his children until the youngest child is 18 and this could give K the right to remaining the property until then.
At that point K would have to leave the property and it would revert to G.
In the mean time K would have to pay the mortgage from her child maintenance and other sources of income.
However in addition K might have a small financial claim based on the engagement and any implied suggestion that the house "belonged" to both of them - but it would be a difficult argument for her to successfully sustain in the absence of separate evidence of his intentions.
I hope that this is of assistance please ask if you need further details
Paying the rent on an alternative property is a possibility BUT it lacks the security of an owned property - however a deal where he pays K a lump sum to leave and rehouse herself might be attractive given that if she remains in the current house then when the child is 18 she walks away with nothing