Found 5th Sep 2014
Best price I could find, it's £10.99 for a 3 pack or £18.40 for a pack of 6, with free delivery. I only mention this because there was a recent deal on Groupon for a 3 pack at £11.99, so I started comparison shopping. I was going to buy from Medic-animal at first but they charged delivery which made it more expensive. Then I found this deal with free delivery. Apologies in advance if there's a better deal out there, but when I looked this was the best I could find.