This table weirds me out because if I were in the military I’d apparently be equivalent to a captain or colonel and that seems like way more responsibility than I actually have.
https://en.m.wikipedia.org/wiki/Civil_Service_(United_Kingdom)#Grading_schemes
It's a bit of a quirk of the civil service in general that pay grade is directly tied to hierarchical seniority.
I basically leapt directly into a senior-ish position by virtue of it being a specialised role that commands a high-ish salary.