yes it can be retrofitted. If you already have the wiring in place it's a 15 min job. if you don't have the wiring in place, you can wire it all up yourself using my how to guide.
You'll need these bits to retrofit it, a CC ECU, master dash switch and steering wheel controls:
http://www.ebay.co.uk/itm/ROVER-75-M...0AAOSwzgBY3XmR