While swapping nearside wheels front to back, cleaning the wheel arches etc I noticed on the rear suspension a strangle link from the lower arm to a fixed point above. It’s the green plastic part. It appears to transmit the movement of the lower link to a sensor as there is a plug and cable attached. The link is double jointed and not very strong so can only be for sensing suspension movement. I’m guessing it might be to either Electronic Stability Control - I don’t have DCC . Any one any thoughts?

It's the sensor for the headlight levelling system.

Thanks - that makes sense.

Also controls rear brake bias. so you get more rear braking when you have a heavy load on.