On Mon, 1 Oct 2012 16:40:17 +0100, "Bert Coules"
wrote:

I gave up temporarily but later took the tap spout to a small plumber's
merchant (where I should have thought of going in the first place). There I
was told that there should be no O-ring: the sliding surfaces simply rotate
against each other. What about lubrication? Oh - use Vaseline, the chap
said.

Tip:
Only believe what storemen tell you if you already know they know what
they're talking about.