Inheritance



My son recently died in Turkey. Although he did not have residence, he had no intention of returning to UK. He owned a home in Istanbul, which was bought with a loan from me, with no written agreement except bank records. As he left no will, was unmarried and had no children, his mother and myself are his heirs, under both UK and Turkish law. She has agreed that I should be sole inheritor.
My questions: does inheritance take place under Turkish or UK law?
How can my ex-wife state that she does not wish to inherit?
Will I have to pay inheritance tax on the part of the value of the property that is still owed to me?

Thank you!+