You can get the kit from Seat, its £130.
In the kit you should have the fogs, 2 grilles, wiring loom, a new switch and a wiring loom.
First you replace the switch by pushing the actual switch in, and turning it to the right, it'll click into place, then you pull it out. Remove the connection from behind it, and replace with the new one.
Remove the front bumper. (There is a tutorial on my website for this).
Fix in the new loom, there will be clips on it, clip it neatly onto the bumper, leave the wires dangling where the fogs will be, have a spanner handy and fix in the grounding wire to the grounding point (next to the battery).
Refit the front bumper, ensure the wires for the fogs are not caught up.
Go to your light unit (drivers side) and remove the connection, snip wire 03 (green) and fix that into your loom for fogs (This is the + connection to Fogs, comes from the light switch).
Grab the bag of fixings, plug in the fog units, TEST!, screw them in, fix the grilles and jobs a goodun!
If you go to a garage they are likely to charge you something silly, the job took me 6 hours
(Yeah, laugh! How long did it take you to remove the bumper the first time) but its very easy.
The results are OEM looking,
Before and
After.