American book here
https://archive.org/stream/lyonmemorial01lyon#page/12/
This makes the founder of Harrow the cousin not the son of the John who married Emma Hedde.
Apparently the cousin and the son were both born about 1510 and had fathers called John and wives called Joan. But the son lived at Ruislip and Stanmore and had kids.
* Henry
** Henry, of Ruislip, 1440
*** John, of Ruislip, 1470, m Emma Hedde
**** John, of Stanmore, 1510, m Joan
***** William, m Isabel Wightman
** John, of Preston, 1450, m Joan
*** John, of Preston, 1510-1592, m Joan
** Thomas
*** Sir John, 1490, Lord Mayor
But somehow on WikiTree, the 6th Lord Glamis has become the father of Emma Hedde's son, instead of his namesake that she was married to.
And conflated-John's wife conflated-Joan has become a Lyon by birth, at the price of being older than her grandmother.