S3 dash clocks

I have a Leon Cupra and Im looking at converting my dash clocks for an S3 unit with driver display. I have a problem, the k line interface connection is in the grey plug on the rear of the unit. My Leon only has blue and green plugs. So does anyone know why the grey plug exists and if its on all models, all years?

I need someones A3/S3 to plug my dash in so I can read the immob code and program my key! Any takers?!