I no longer have a Rover, but have some stuff left, if you're interested. Pictures below of a Connects2 kit and universal patch lead. Please note (a) I had various stereos fitted to the Rover over 12-13 years of ownership, and I can't remember what this kit was for; (b) although it claims to be a universal kit, I can't guarantee you can make it work with yours.
But if you want to have a go, £20 delivered
The kit (not sure if the little loom on the left is part of it)
The connectors
Installation guide
Universal patch lead
Let me know if you're interested (or anybody else who reads this)