I think there's something to be said for maybe saying test first. I tend to find writing tests second a little harder. If its a big complicated feature, its much harder to go back and try to think of all the test scenarios needed when its finished, there might be an edge case or a semi obscure case that may have been apparent at writing the code but gets missed when looking back and writing tests. But its preference.

Actually, the pay band ranges from a Band B to Band C in the civil service. Band B is entry (not junior though) and Band C is just below senior. ~40K for a Band C civil service software developer in London is about average.