I keep intending to make something similar myself.
I don't use microbore or the valve, I use tricoflex and the one way hoselock connector, so to cut the flow I just pop the connection...
And...um, I'm really pro....I tie my tricoflex around my waist and do it that way
Yeah, I know, I look a right numpty
I'll have to do something similar to Gaz and get a valve on the hose
Ian