Neither the will nor the mortgage have any real evidential value in the matter. However, I must warn you that if you push it the will can be turned against you. Your ex will in essence tell the judge that both the direct and indirect promises made by you to persuade her to move in with you were seriously made and that the purpose of your actions persuaded her that the association would be forever and it is only on this basis that she agreed. The fact that you are no longer together (it does not matter who or what ended it) is a breach by you of the contract and she is entitled to compensation as claimed. There may be no hard evidence of any of this, but she is entitled to point to what happened and tell her story and be believed, and to maintain her story under cross examination. Justice in the courts is not a finely balanced thing but is crude, tough and rough and a blind gamble. Legal aid must have assessed her chances of winning at better than 70/30 before it was granted and will also be aiming to reimburse the public purse out of your pocket. A courtroom full of liars is well understood by the judges and their training and the system is designed to weed them out but if you have a bad day or the judge does not like the look of you it will be you who is weeded not her, make no mistake. Letting this sort of thing actually get into court can be a catastrophe, can you not settle even now?