Hmm, I'm not familiar with ball valves, what're they?
Oh and also, I was going to have terminating barbs on the end of the pipe coming off my tee, like this:
But I can't find nuts to screw on the end of here ANYWHERE in the UK. I've searched all over.
I was trying to find a suitable tap as well, but the only 1 I saw was ugly as hell and £10.49 with delivery