1. At the outset, you need to realise that legally speaking, the letter of wishes is not legally binding. Essentially, only a valid will is operative upon death. This is because the formal legal requirements, such as having two witnesses, have to be satisfied before a will or any other instrument is operative upon death. A letter of wishes is not a document which can be sued upon to enforce its terms. It was up to your grandmother's partner to include these specific dispositions in his will if he wanted to make them binding. At the time of signing of the will, he would have received this information as legal advice and he chose not to make them binding. Now, it is purely something that the executors don't have to do. So I would advise your grandmother to accept their goodwill gesture as she is not in a legal position, nor is the accountant to enforce the letter of wishes. Ultimately, a legal action would be a waste of money.
Thanks - I suspected as much.