Well my dev environment started to mess up so thought it was time for a clean install - I’ve been meaning to do one for a while anyway. This guide still works so posting it up here:
The most time-consuming part was copying my home folder to a back up disk (which I started just before going to bed) then copying it back to the new install.
It’s worth a try if you’ve never done it before - I’ve reclaimed about 100GB!! Most of which was in the Application Support and Caches directories, once I’ve installed all my programs it will be interesting to see the size of them, I doubt they will take up as much…