[MusicLoverUK]

What model year is your car? The fog lights are different pre-facelift (MY10,MY11,MY12) and post-facelift (MY13-). If it's an Energy I guess that makes it post-facelift, but those lights in the eBay link look like pre-facelift fogs.

 

[MusicLoverUK]

You will also find that your car doesn't have a switch to operate front fog lights, so you would need a new headlight control switch as well. I know in my old Astra G which din't have fog lights the loom was there with the connectors just tied up out of the way, but on the J quite a few of the looms are made to suit the different configurations. I don't know specifically if there's a variant of the loom without fog light wires, but it wouldn't surprise me. You just need to crawl under the front of the car and have a look what's there. If the wires are there then the first thing to do is see if you can get power there before you spend any money on buying the lights.

 

[MusicLoverUK]

Rear fog only:
http://www.ebay.co.uk/itm/201205804083

With front fogs:
http://www.ebay.co.uk/itm/271625119053

With auto headlihgts:
http://www.ebay.co.uk/itm/261491197693

 

[MusicLoverUK]

Yes that's right - it;s for your rear fog light. It will only come on if you have the headlights on. To have front fogs you will need two buttons in the middle of the knob there.