I knew this would cause consternation, you can call anyone what you want including using the name Engineer, but a name does not mean you are one.
You may work in Engineering as I do but unless you hold an Engineering degree you are not strictly an Engineer.
Look to the real world and Industry, the Engineers you talk of within the service would almost all be considered as Technicians. Engineering Officers would not get a job (lol) Engo's are better suited to project management imo.
Engineer jobs in the real world require you to have an Engineering degree.