After putting this job off it was actually pretty straightforward. Main points to note were that my 2012 didn't have the same bolts as the one in the guide retaining the map pocket (you don't need to remove it. H I fixed the seat heating too) or control panel but it was easy to see what was needed and where.

If anyone else needs to do it, follow the guide in the wiki to remove your seat from the car and then the side control panel and the plastic the control panel mounts on to. I also removed the seat belt clasp cover. You can then gently lever the seat cover off of the seat frame, the wiki guide covers this too. I started at the back, under the seat back, then the sides, then the front.

Once done, you can pull the cover and foam base out easily. After that, undo the velcro under the foam, then fight the hog rings to get the cover off of the old foam base. Transfer over the air guide (mine are heated and cooled), refix the cover to the foam with hog rings or zip ties and then reassemble. Not too challenging but take lots of pictures of electrical connectors, bolt holes etc. I couldn't work out where one piece of plastic went and spent 30 minutes working it out!

Good luck with yours.