The situation
A UK B2B software company with two products, ISO 27001 and Cyber Essentials, and customers who send long security questionnaires. Its sysadmin left.
What I did
Took over the servers, documented them, and became its part-time infrastructure lead: patching, monitoring, architecture advice, certification evidence and incident cover.
Now
Four years later the arrangement is still running, and a major platform upgrade is being planned the same way.