Amazing; thanks for coming back with all of that.
I have some more questions though!
1) For the power supply unit, do I just get a normal plug and wire it into the live, neutral and earth on the unit then take one of the V- & V+ into an XT60 to attach to the charger? Dumb question, but just so I'm clear! As I said, I don't like playing with mains electricity! Is a 13amp plug sufficient?
2) Something like this would work for parallel charging?
https://hobbyking.com/en_us/hobbyking-parallel-charging-board-for-6-packs-2-6s-xt-60.html
3) when parallel charging, will the auto-cut offs still work? Do they work individually work on each battery so if one was 50% charged and the other 75%, it wouldn't damage the one at 75% by charging it for too long?
Thanks again, this is very helpful.