Just realised I'm overdue to replace the cartridge in our two-year-old fridge.

I expected that I might get it at Bunnings or M10 but apparently not (looking online). Also can't get sense from the Harvey Norman or Noel Leeming sites on this.

There are some specialist retailers online but the whole thing seems to be a little less simple and less common than I thought it would be. eg. it's not immediately obvious how to align the fridge and cartridge model numbers.

Would appreciate help and comment. Cheers.