Here's my solution...
I've got a varie stream regulator (Left the pressure switch connected) then at the end of the hose where the pole connects to it I've got a normal plumbing isolating valve with numpty, cost about £2.00 from screwfix last's for ages and ages
To fit cut two small lenths of copper pipe(the small lenght will not contaminate the water) fit to either end of the isolater (compression joints) then push hose over each side (tight fit) and secure with jubilee clips. and there it is a simple on/off switch that can take all the dropping and knocking that you can give it, and cheap...
Alan