Insignia A20DTH spurious plug

I am at the end of my tether trying to find a home for a plug at the back of the A20DTH engine, it is part of the 'loom' that feeds the crankcase sensor, differential pressure sensor, swirl flap actuator etc etc and is a single wire coloured yellow/light blue with a small plug on the end coloured yellow with a green rubber seal.

Does anyone know where this should go or have wiring diagrams for a 59 plate insignia tourer so i can try and trace it?

Any help greatly appreciated