Did 6 new cleans today all in same cul de sac.....I did all the fronts, frames and glass with good rinse then went back to start to clean glass again...tried uncoupling the brush and ended up having to get mole grips on male to pull it out of female....tried 2 other brushes and they were the same...and yes I did pull the collar back first to release the coupling...any ideas why so difficult,really had to pull....Gardiner brushes and fittings.