Does anyone know if it's posible to fit a rearview camera the vehicle that already has a Columbus, front & rear optical parking sensors and park assist?

Is so, I'd be interested to see a photo of what the Columbus display looks like when reversing.

yes

Not a skoda columbus, but I fitted a Camera to a car that had park assist and optical parking display

http://i117.photobucket.com/albums/o45/scotty-boy_2006/3920855c.jpg

Thanks for the prompt reply - that's very helpfull. Which bits did and use, and where it you source them from? Also, is it a simple "plug and play" install, or does require any coding changes?

Take a look at this link: http://www.my-gti.com/2837/installing-a-golf-mark-vi-rear-view-camera-rvc-into-a-golf-mark-vi

There is more information on that site as well as on VWNAVI website.

The picture above is an RNS-510 (VW original version of Columbus) so if you can get it working, it should look pretty much the same.

there's one that fits instead of a number plate lamp for sale on Ebay

http://www.ebay.co.uk/itm/VW-Rear-Reversing-Camera-Passat-CC-Polo-Jetta-Skoda-/260739891082