Steering wheel radio control buttons

I have recently bought a C4 VTS which I purchased as non-runner. After getting it running I have moved on to sorting out the electrical problems.

The main one was central locking not working. After fitting a old head unit I had in the garage and re-installing a new key that worked.

Now my problem is with the head unit and steering wheel control buttons. They do not work! There was already a Connects2 box with all the wiring in the car. It all connected fine and all worked.

This was until I thought the wires from the Connects2 box might have something to do with the rear parking sensors not working. There is a brown wire from the box that says rear sensors so I tried it again the only 3 wires left from the cars wiring. 1 a green wire, 2 a pink and 3 a light purple and white wire. This did not make the sensors come on.

Now the controls for the head unit from the steering wheel do not work. the rest of them do for the trip comp and cruse control and lights on the dash.
I have checked every fuse on the car and also the one on the head unit and nothing is blown.

I know it's a bit of an essay but I'm stuck and would be great full if any one has any ideas how I can get the buttons working again.

thanks