How to remove this tap cartridge?

[Ptew123]

Any ideas? There seems to be a retaining ring with 4 little holes in but it ain’t budgin! Any ideas gratefully received!

 

[ShaunCorbs]

Have you tried a flat screwdriver with a hammer in the holes to shock it eg undo

 

[Ptew123]

Have you tried a flat screwdriver with a hammer in the holes to shock it eg undo

Thanks Shaun - just had a go. Doesn’t seem to want to budge (I admit I’m not hammer too hard in case it does need to unscrew). Not seen a tap like this before - it’s a Bonade (German) if that is any use/clue!

 

[ShaunCorbs]

Yes will need to come out it might be reverse thread stranger things have happened