Electronic advice please.

Hi, 
I believe you have identified the problem,  digital signals won't work on rca connections.

 The camera IS transmitting digital video via that fixed usb lead. 

Also the thumb drive and the TPMS also transmit digital signals so won't work in the rca plugs either!

The reversing camera is an analogue signal, which explains why that works on the rca socket.
 
I have decided to put the camera and the TPMS on the two usb connections and live without the additional memory.  So I have deleted a lot of unnecessary apps from the headunit hard drive(mainly a satnav app with an offline map)  to make space for a selection of my music collection.

Thanks for all your help,  Hope you enjoyed this problem as much as I did,😆 🤣 
 

Glad to be of help. Problems of this sort intrigues me in order to figure out what went wrong. I started blank just wanted to help, but we nailed it in the end.

Can't beat a red herring or two.