Please answer the following question: What is the full name of the person who Winston Churchill bought Chartwell from a family member?  Answer the above question based on the context below:  Chartwell is a country house near the town of Westerham, Kent in South East England. For over forty years it was the home of Winston Churchill. He bought the property in September 1922 and lived there until shortly before his death in January 1965. In the 1930s, when Churchill was excluded from political office, Chartwell became the centre of his world. At his dining table, he gathered those who could assist his campaign against German re-armament and the British government's response of appeasement; in his study, he composed speeches and wrote books; in his garden, he built walls, constructed lakes and painted. During the Second World War Chartwell was largely unused, the Churchills returning after he lost the 1945 election. In 1953, when again Prime Minister, the house became Churchill's refuge when he suffered a devastating stroke. In October 1964, he left for the last time, dying at his London home, 28, Hyde Park Gate, on 24 January 1965. The origins of the estate reach back to the 14th century; in 1382 the property, then called Well-street, was sold by William-at-Well. It passed through various owners and in 1836 was auctioned, as a substantial, brick-built manor. In 1848, it was purchased by John Campbell Colquhoun, whose grandson sold it to Churchill. The Campbell Colquhouns greatly enlarged the house and the advertisement for its sale at the time of Churchill's purchase described it as an "imposing" mansion. Between 1922 and 1924, it was largely rebuilt and extended by the society architect Philip Tilden. From the garden front, the house has extensive views over the Weald of Kent, "the most beautiful and charming" Churchill had ever seen, and the determining factor in his decision to buy the house. In 1946, when financial constraints forced Churchill to again consider selling Chartwell, it was acquired by the National Trust with funds raised by a consortium of Churchill's friends led by Lord Camrose, on condition that the Churchills retain a life-tenancy. After Churchill's death, Lady Churchill...
Answer:
John Campbell Colquhoun