Have you tried the John Guest fitting?
Yep and I find they come apart hence keeping it simple.
Have you thrown away the little red clips that come attached? 
When I first got mine I took them all off & chucked them. Assumed they were for transport or something. 
Turns out their not. 
They stop the hose pulling out accidentally. 
On my next purchase from Gardiners I asked for 9 new red clips. They chucked 'em in for nothing. 
Hose hasn't popped out since.