Can anyone tell me where I can find a technical document for the Bolero radio and the columbus Sat nav units. I want to see what input and output jacks are available at the rear of the units and also to understand what can be connected to each. Picture of the rear of these units would be ideal.

You can find diagrams of all the wiring connectors on Google images. There are no RCA jacks on them, you need to use a converter if you wish to add external amps.

What things do you want to connect?

Sorry to but in, but, I had been wondering if it was possible to add a video feed and if so, how to select it to show on the display. I'm thinking rear-view camera to help with backing up to a caravan hitch. Lazy I know, but its a bit more tech From what you say Keith, I guess I'd need to 'digital-ise' the camera feed, in a similar way to the TV option?

You can find diagrams of all the wiring connectors on Google images. There are no RCA jacks on them, you need to use a converter if you wish to add external amps.

What things do you want to connect?

Thanks for the info - I want to ge the TV working on the columbus sat nav and for the bolero I have a TOMTOM device that I want to somehow connect through the sound system, would that be possible ?