"Skilled technical specialists don't get paid more, the computer software used to decide the pay rate for a job seems to mark specialist skills down - that's not just in IT, that's across all specialisms."
Unsurprisingly nothing seems to have changed since the 1980s. Promotion from SSO to PSO depended on responsibility but that was defined as management responsibility. The fact that in my speciality there was the individual responsibility for giving evidence that might put someone away for life didn't count.
I bailed, went into IT and the money started going up and up. I think it came as a slight shock to my former employers but from what I heard, not enough to do anything useful. However, entirely coincidentally, I was offered the promotion to PSO without any of the normal procedures as soon as I handed in my notice.