From August to October 1558 he was busy directing works on the Island of Inchkeith, including the construction of a munition house, to complete an artillery fortress designed by the Italian military engineer and architect Lorenzo Pomarelli.
[8] After the death of Mary of Guise he remained in Edinburgh Castle and was charged with neglecting his duties as a warden and Master of St. Pauls Work.
[10] After the reformation of 1560, MacDowall was excluded from the town works, which recommenced with the conversion of a part of St Giles Kirk into a new Tollbooth.
[11] Although MacDowall was not again employed by the town, he worked for Mary, Queen of Scots, and repaired a pair of organs at Holroodhouse.
[23] After William's death, in March 1580, his vicarages of Leswalt and Inch, were given to Richard Waus, a natural son of Patrick Vans of Barnbarroch.
[24] George Bannatyne (1545–1608), an Edinburgh merchant who made a collection of Scottish poetry, compiled a family "Memoriall Buik" in which he recorded the names of the godparents of his siblings.
The list includes William (1557), and another priest sir Robert Danielstoun or Denniston, Parson of Dysart (1551) whose brother served as a master of work, and keeper of Linlithgow Palace.