Andrew May wrote:
Fitted a new kitchen tap at the weekend. The type with a base that goes
into a single hole in the sink with a nut on the underside. But it came
with a rubber washer to go between the nut and the sink and however much
I tighten it there is some give and the tap has a tendency to lean when
touched. I can't see the point of a rubber washer and was wondering if
there was any reason why I should not replace it with a nylon one to try
to give a bit more stability.

Andrew
Are you sure the rubber washer does not go on top of sink?