Not as cheap as the deal I posted two years ago at £19.73 though appears a good price nevertheless.
Last offer posted on HUKD was just over two weeks ago: 1 years' supply 60 Day Water Filter 6 pack for £15.43 with Amazon Prime.
These fit all Aqua Optima filter jugs, filter kettles and water chillers.
Each filter lasts for 60 days - approx. 200 litres