hello mate,
YES!!
thank every god in the universe! It ended up being the wiring loom from the throttle to the injection module (something along those lines)
a guy called Tom off here (westsrenault) pm'd me and said he might know what it is and then I drove to cambs,picked it up a week later and BANG the problem was gone!
Hasn't done it since...touch a big fat massive plank of wood!