Renault Megane 1.9 Dci 53 plate won't start?

Our 53 plate renault megane won't start. The dashboard says injection fault. The AA have been out and plugged it into their computer which says there's plent of pressure (330 mb), cam shaft sensor is working, glow plugs are firing. According to his computer there's nothing wrong with it - it just won't start (although the car appears to be trying to turn the engine over).

Any suggestions would be appreciated before I have to sell my soul to renault and get them to take it in.

Thanks

Dave