The STC pictured is defect, it's only being used for figuring out the fit and I'll pull one out of another old controller or buy another down the track.
Yeah I will be for sure thanks Yob, I'm waiting for a sparky to have a look and advise before proceeding from here, I was going to have an earth into 1 lug connected to the enclosure and earth everything from there in my mental schematic. It will me drawing near on 50A upon full completion of my project and have been told by a sparky friend - "Your mains would be 16mm which can safely draw 80A; so you will be limited as to what you can use at the time that it's up and running."