All the single status/job evaluation stuff is going to do nothing meaningful for public sector pay and conditions really.
What it will do is iron out some of the inconsistency across individual councils - for example large authorities have lots of admin staff and between different service areas or directorates their pay can differ by several thousand pounds a year, often for no good reason.
Each job is scored against a set of evaluation criteria - there are several systems an authority can choose from. Once they have scored each job (not each person) they will align a payscale with the scores and everyone will find out their new salary and conditions. Most council's say the process will be cost-neutral so for anyone who gains other groups will lose.
The process is full of holes though - some places have used job titles which is fundamentally flawed - the Council I'm doing some contract work for has "System Administrators" in different areas doing completely different jobs and as such their pay ranges from about £15k - £35k. They wanted to evaluate these posts simulataneously, which was obviously never going to work. There is also no accounting for scarcity of skills or professional qualifications to a large extent, but authorities can set their own "market supplements" to adjust salary, but these are not pensionable so the staff ultimately lose out.
What the process won't do is get rid of the differences between very similar posts in different authorities. A guy I was working with has just moved to a neighbouring authority and picked up an £8k pay rise and a lease car for a pretty much identical job in a similar sized council.