Yes sorry £12.50 per filter when buying 4.
The other issue I have with using bottled water is that if buying in the most cost effective and least plastic wasting way then obviously 1.5-2 litres bottles are the way to go. However I sometimes barely use 300ml in the tank each day so a 2l bottle sits open for nearly a week. It’s in the fridge but I’m sure I’m not getting the best quality of water five days after it’s opened.
The reviews on the Zero jug seem a bit mixed, but unsure if they’re just from people who haven’t changed the filter as suggested.