EDIT: - I'm thinking that black box may have something to do with it. Try to take a good clear picture of that black box on the back of your radio. Are there any other wires coming from it other than the one going in the top like in the picture?
Interesting. Have you looked at the Kufatec Fiscon website? Its very expensive BT equipment. That leads me to beleive that it could be to do with SEAT, as in it's their preferred manufacturer of their BT systems. What you have on the back of your radio is alien to me.
You either have DAB on that radio or it's something to do with the BT system. Obviously you don't want to go unplugging everything because you may need the radio code. Is there any other wire coming from that black box other than the one in the picture?
I have two things coming out the back of my unit. I have the large connector like you have, furthest away from the camera in your photo, and I have an aerial lead. Looks like you have more than that.
That lead with the white connector with the bit of pink on it, that looks like an aerial lead, but what it's going into, I dont know.
So, what to do next is to try and reach your arm in the compartment where the radio sits and feel your way through to the back of the glove box.
This is possible. I've done it. If you feel box with a or some wires coming from it, that could be it. If you don't, then try to take a good clear picture of that black box on the back of your radio.