As he celebrates his 30th birthday today, Prince William is set to inherit an estimated ÂŁ10 million from his mother’s estate today, which means he can now take control of half of a trust fund believed to be worth more than ÂŁ20 million. Princess Diana bequeathed the trust to the Duke of Cambridge and his brother, Prince Harry, who were 15 and 12 at the time of her death in…