Hi

I got my relay from Maplin...part number N00AW. This is a 12v 30Amp SPNO relay

The blue and white connections are connected to the TV module which is next to the battery (under the black plastic cover which is under the metal dome which is under the spare wheel in the boot).
If you have a TV module, as you remove the plastic cover, you'll see the Nav computer on the left and the TV module on the right. If you don't have a TV module, the cables should be wrapped down there somewhere.
The white connector may have a thin white loose wire cable tied to it (at least mine did)...not sure what this spare cable is for but at least you can use it to identify the white plug