I picked Thomas Gainsborough and I additionally suggested that the bank note should feature one of the twin portraits of his daughters, Mary and Margaret - specifically, the one which is held in the Victoria and Albert Museum and just happens to be in bank note format:
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Not only do you get a visual artist but you get two girls and you get childhood. You also get a story of what looks like the desire for ownership trumping the demands of art.
You will notice that a vertical line runs down the middle of the painting. The work was painted around 1758 and inherited by Margaret Gainsborough, on the right (the younger of Gainsborough's two daughters). It then passed to John Jackson RA and when next transferred was cut in half, one half going to W C Macready, an actor, and the other to John Forster, Dickens biographer. Forster eventually re-united the two halves of the painting and bequeathed it to the Victoria and Albert Museum in London in 1876.