Is that all it is? You must be able to find a spare +ve feed on the back of your fusebox for that one connector. You'll have to drop it down and have a look, i'm thinking position Y, bottom left of the single pins as you look at the fusebox with the relays and fuses facing you. Earthing is simple, there is a block underneath the dash above the fusebox, loads of brown wires going to that. The fuse holder will clip on top of the fusebox as well.
**Edit** Position Y1, just checked the Fusebox sticky by rubjonny.