armouries
I was googling topics related to members of my family tree when I came upon a website for the Ordnance at the Tower of London. I am unsure as to why I hadn’t stumbled upon this site before, but that is the nature of research. Serendipity is an important component.
The website [https://www.royalarmouries.org/tower-of-london/things-to-see/power-house/institutions-of-the-tower/ordnance-office] deals with the Ordnance office’s role, and includes a lot of historical content. A goldmine really. The best part was a list of the clerks of the Ordnance from 1815-1855. And of course, there listed was John Cutler, who worked there according to the site, from 1815 to 1826. So the question of when he left is answered.
Also interesting to note from this source is the presence of addresses for the clerks. Now some clerks lived in the Tower of London, and their entries indicate what number house they were assigned. Others, like John, lived offsite. John’s address is not listed, but I know he lived in Kennington/Camberwell. Surprisingly a number of his co-workers also lived in that area. Looking at a map of London, the Tower is a fair distance away from Camberwell, and though there appears to be a main road leading to the bridge, Camberwell does not look to be all that convenient. So why did a number of the clerks live there?

More research is definitely required.