Nextbase 512GWRC REAR camera and connecting wire wanted

I already have a hard-wired Nextbase 512GW.    I also have a really small camera for the back (to go within the loop behind the driver’s seat) but don’t know if I’ll be able to feed its output into the dedicated socket on the host camera.  I’m interested in having a go at working out what the wiring etc is between the front and rear Nextbase cameras.  I’ve spent the last couple of days looking for a service manual etc, no joy, so the last resort is to have a careful electronic look at one.

If I have a sample of the Nextbase Rear Camera (probably a bit bulky to actually use) and its wire to examine I might be able to work out what signals and connections will allow me to plug in the tiny camera.  I can probably also repair or work around the usual fault of the socket breaking off the 512GWRC circuit board.

Does anyone have one of these they don’t want or is broken, and are prepared to lend or give it to me?  I might be able to restore a broken one, and return it working if that helps.

It’s a daft thing to ask really when I can buy a new one (old stock now though as they are obsolete and no longer made).  But I like a challenge, and it could be quite a simple solution with variations on the USB theme. Or it could be impossible with Nextbase carefully locking out any other cameras.

Please PM me if you can help.

Thanks

Richard