Trailer Wiring Connection

I occasionally pull a small utility trailer.
I have a Curt hitch on the S-Type.
I want to connect the light wiring.
I found a page 08.3 in the wiring diagram showing a trailer connection module.
I don’t think my car has this module.
I found an unused connection socket in the right hand side of the trunk (boot).
It has 13 wires to it.
Color codes are OU OB OU OU BO BY BN BY BO BW OG OY OY.
These codes do not quite match diagram 08.3
Does anyone know, what is this connection?
Is this for the trailer wiring?