Abraham,
Thanks for the suggestion. I did upload the installation file and schedule it for installation onto my Macbook Pro - 2 minute window from the exact time. Unfortunately, 20 minutes later, and 1 restart too, it was not installed. No Sophos icon was present in the app bar across the top right.
I tested this theory by manually installing Sophos and rebooted (again, just to be sure). The Sophos icon appeared correctly in the app bar across the top right.
So, it is pretty clear that the scheduled installation did not work.
I hope there is a solution that works, as time goes on, the amount of installations I have to perform increases.