So the new dream home is not actually relevant here.
He has a claim against the property even though it may be in your sole name, if he has contributed to the fabric or the capital of it which clearly he has done. Quantifying that is not going to be easy and the easiest way of doing it is to look at what the house would have been worth with his input and what it would be worth without his input and then negotiate around that.
You would be entitled to deduct any money you gave him in respect of his debts.
In respect of the £10,000 from his father and the car, depend on who has the car and whether this was a gift or a loan which was to be repaid at some stage in the future. There is only £15,000 from it in any event, less the finance outstanding gives an amount of money from the car of £5500.
I don’t know why you transferred the £4000 over to him.
My suggestion would be asking what he wants.
You can then apply that to the house value without him and the value with him and then look at paying him something.
Incidentally, if ever you get into this situation again, if the house was in joint names than regardless of what each of you put in, it would now be split 50-50 unless you had previously agreed otherwise.
You could have avoided this by having a cohabitation agreement where he would agree to have no claim on the house.
Can I clarify anything else for you?
I’m happy to answer any specific points arising from this.
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