We have bathroom suites called Ideal Standard Ravenna fitted nearly 5
years ago. The taps are 1/4 turn ceramic disc, and there do not appear
to be any retaining screws on these taps to enable removal of the tops
and thereby gain access to the tap cartridge.

They are difficult to describe but look a bit like the alien spaceship
in "Alien" but in stainless steel insead of alien steel. Do I just
insert a screw driver into the very narrow gap between the bit of the
tap that moves and the bit that doesn't, and twist gently in order to
get off the tap top? In this gap is situated the red and blue disc for
hot and cold indication.

I think it is time they all had a bit of a service and clean up.

Any help most welcome.
John
In limine sapientiae