The mystery...

Now im not one for stirring up trouble but... I was looking around a few agency sites, and Leith up in Edingburgh have some impressive clients and some adverts that I remember, especially this one from Carling...

Visit4info confirm that Leith made the advert, but Farm communications (who we visited for a crit a couple of weeks back) also have it on their website in their portfolio. I'm confused. Who made it?