I can get the tap off so that a washer can be replaced, but how on earth can one get access to the O-ring if that is leaking? It is not possible to take the tap's head off, since the ceramic inlay will not budge - and is there a nut under it anyway? Bristan's own website is 100% uninformative in constructive terms for these expensive units.

O-Peter, July 2008

There is no O-ring. Just undo the small nut at the top of the tap, then wrap about 3 inches of lightly rolled PTFE tape (just hold one end and roll it forwards across your leg) around the spindle and screw the nut back down. It adds to the packing that performs the sealing function.

My plumber told me, July 2008