I know it does'nt exactly answer your question Luke, but I just went back to using hozelocks. I put a barbed adapter on the end of the microbore to bring it up to a short piece of 1/2 " hose with a hozelock on the end. Reason being I must have gone through atleast 3 of those airline style valves from 2 different suppliers in as many months! Gets annoying in the end and they are costly. Personally I would rather use hozelocks now and if I run out of spares I can easily buy one from any garden or diy store whilst out working with minimal downtime.
Simon