This whole thing about "... if you want more money then move south, come and join us!" is a red herring.
If the gradings were reversed: LACC/TC were band 4 units, ScACC/MACC band 5, how many controllers currently at LACC/TC, living settled existences, kids at school etc BUT without any connections to Scotland/NW England, would willingly upsticks and move, purely for the extra money??
As far as I can see, the only ones to have voluntarily moved to my unit from LACC/TC over the past few years are ones with strong Scottish connections/ family reasons (I doubt this is just self fulfilling i.e. there are a huge number applying, but the majority don't get through because they don't have compassionate reasons, therefore we don't see any others up here).