Dripping Damixa Filterflow mixer tap All aspects of plumbing questions and answers, help, tips and information

[twl80]

I have a Damixa Filterflow mixer tap that drips, the drip coming from the cold side with the two-way handle for normal or filtered water. I assume that the whole cartridge will need to be replaced, but having got the tap handle off, I'm stuck as to how to get it out as (presumably because of the Filterflow) it's not a normal-looking cartridge (see photo). Also having read some forum posts about Damixa, will I even be able to get a replacement? Many thanks for any advice.