Towbar electrics not working on bike rack

[JD03]

I have just used my electrically retractable factory-fitted towbar for the first time. I am connecting a Peruzzo Pure Instinct 4-Bike Towbar Cycle Carrier which is a 13-pin plug to the electric socket on the Enyaq towbar, but it is not working. I get no sounds that should occur for example when signalling, and no lights on the cycle rack. This works fine on my other car with a post-market fitted toawbar and 13-pin plug.

Has anyone experienced this and/or any suggestions of what I could do?

Many thanks,
JD