My Father in law has just passed away, he has a will in place from 2011 and my Mother in law has just received a legal letter from his ex wfe, based in the US who has a letter signed by him and witnessed from the 1970’s saying she would be entitled to half his estate when he passes. Clearly since then he remarried, had two children and has put in a will that is clear on who the beneficiaries would be which does not include his ex wife. Does she have any grounds for a claim?