Clearly William was married by 19 Jan 1498 but by that date, his daughter Elizabeth was already married to Richard Brown. That marriage was in 1493 placing Elizabeth's birth prior to 1481 and William's marriage prior to 1480.
N.B. Elizabeth is conflated by Arnott confusing her with her with Elizabeth, her aunt who married Robert Colville. and with Elizabeth, her second cousin who married William Sempill.[2]
Sources
↑ 1.01.11.21.3
Arnott, James, "The House of Arnot and Some of its Branches: A Family History", Edinburgh: T. & A. Constable, 1918, Hathitrust,
p. 160
↑
Arnott, James, "The House of Arnot and Some of its Branches: A Family History", Edinburgh: T. & A. Constable, 1918, Hathitrust,
p. 160,
p. 160