My father recently died and appointed my older sister and younger brother as co-executors. There are four beneficiaries to his estate, myself and my younger sister being two of them. As co-executor, my older sister has refused to communicate with my sister and I, refused to distribute assets of my father's bank and building society accounts to my sister and I until his house has sold, but we suspect my older sister has already distributed monies from bank and building society accounts to our brother. What do we have to do to remove our older sister from being executor of my father's estate and turn everything over to a solicitor to handle?