So loooonnng story short-ish. We have a dripping tap. It’s been this way for a while and has slowly got worse (Like Chinese water torture). It’s almost definitely the cartridge. I pride myself of being pretty handy with tools and being able to come up with solutions to tricky problems, however this tap has me stumped! Some people with say just get a new tap but this tap was ‘expensive’ and if all it needs it a new cartridge then I’ll destroy it trying to get it open before I buy a new one ☝️. So I’ve tried using one of those boa strap spanners and nope, I’ve tried using a two pin angle grinder spanner... (see photos) and nope. I’ve even taken the tap to my local engineering firm who strapped it into a vice and and had a two pin spanner that fitted and even they couldn’t open the thing?!? So far, short of heating it with a blow torch (no doubt would melt the cartridge) or soaking it in some descaler and go again I’m a bit lost. I did buy the tap originally back in 2007 but unfortunately the kitchen fitter threw out any information/ instructions that would’ve come with it so I’m clueless as to what brand or model of tap it is? And can’t remember where I bought it from? Any help is very very very welcome , suggestions of how to open, how to free it up or even a better place to go to get advice?