Lamona Rieza Monoblock cold tap leaks
 

I'm looking to change the washer or Cartridge on this tap as when the cold water is running there is a small leak from the cold turn handle. Ok here's the bit where I need advice, I've removed the screw from the cold side but the handle does not come off. Would this be because of a build up of crud inside or do I need to unscrew anything else, although no other screws or grub screws visible. Is it a case of a bit of force which I've not tried in case something breaks. thanks in advance

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