I think the real contributing factor as far as accidents are concerned is that just before the camera the speed limit falls from 70mph to 50mph.
I know the camera very well, and anyone who drives the road regularly is wary of that sudden speed limit decrease. The camera should be removed and the speed reduction retained - then motorists would only have one thing to contend with. It would be interesting to see what would happen to the accident statistics if that was tried.
That single camera generates around £1million a year for Essex County Council, and I can't see them giving that up without a fight.