By Rob Lenihan A British businessman is looking at a potential 60-year prison sentence in a federal penitentiary for allegedly violating sanctions imposed on a Russian oligarch. Graham Bonham-Carter comes from a long line of big names. The British businessman is a descendant of John Bonham-Carter, a member of the British Parliament and a barrister in the 19th Century; the artist Hillary Bonham-Carter, whose portraits of her cousin Florence Nightingale are held in the National Portrait Gallery; and Arthur Thomas Bonham-Carter, a judge in His Majesty’s High Court of East Africa. Bonham-Carter, 6…