Thanks for the info chaps, I clearly wasn't using the search facility properly.
Having now read the thread it seems that the AS350 might suffer from 2 problems a. jackstall like the gazelle because the hydraulic servos are not man enough for the job. and b. another hydraulic problem that leaves the controls feeling 'locked' and can occur at high DA without neccesarily harsh handling being required.
I taught/demoed jackstall at CFS and Middle Wallop and it doesn't feel like the controls 'lock' - it feels like retreating blade stall since the highest aerodynamic back loads are on the retreating side and that is where the jack stalls. If the controls 'locked' you wouldn't be able to take the corrective action of reducing the severity of the manoeuvre to recover.
Answer - don't fly French helicopters.