How do I open up this old kitchen mixer tap?

[DIY10291]

Hi, I have an old kitchen mixer tap which has gradually deteriorated - it is now quite clunky and takes a lot of force to fully close it. I want to leave the plumbing alone if possible (so not replace the whole tap).

However, firstly I can't see how to open it up - I can't see a cap to pop out/unscrew to access the screw to open it up (that is normally behind the hot/cold symbol). So first question is how do I get it open? I tried levering the cap off using the small indentation visible in the close-up, but a little piece of plastic snapped off.

Secondly, once I get it open, what will be inside - is it likely to be a standard size cartridge like https://www.screwfix.com/p/flomasta-35mm-ceramic-tap-cartridge/6086x? If it is, will changing that make it work like new again, and how do I know which size I'll need? Or, for single-lever kitchen mixer taps like this, can you get reviver kits like https://www.toolstation.com/lever-basin-tap-reviver-kit/p70902? Might be nice to get a different handle that way. Thanks

 

[Deleted member 267285]

Try looking for a grub screw if that top part doesn’t come off.

 

[DIY10291]

Try looking for a grub screw if that top part doesn’t come off.

Thanks. Had another look but can't find one.
Has anyone come across this tap before?

 

[Deleted member 267285]

Try unscrewing the top cap?

 

[DIY10291]

Try unscrewing the top cap?

the very top part above the handle? had a go but it's difficult to grip - wouldn't want to break it if I used grips or something and it turns out to not actually be a screw cap..?

 

[Deleted member 267285]

the very top part above the handle? had a go but it's difficult to grip - wouldn't want to break it if I used grips or something and it turns out to not actually be a screw cap..?

Yeah, I suppose. Surely it’s maintainable though, so it’ll either unscrew, the cap lifts off or pulls off (doubt it’s this type though).