On Mon, 15 Jun 2009 13:04:58 +0100, "Dave Plowman (News)"
had this to say:

In article ,
The Wanderer wrote:
I'm guessing you have a 'standard' angled tap connector on the end of the
pipework. Has a reduced diameter 'shouldered' end which just fits inside
the end of the valve pipework, but which should have a fibre washer over
the end of the stub of the tap connector, IYSWIM.

Could just be that fibre washer.

Think the problem with me was the tap connector wasn't exactly square to
the valve pipe. And being plastic you can't exert much clamping force to
the washer. A rubber O ring might have sorted it. When I redecorated, I
took the opportunity to add a service valve and flexible pipe Which has
slowed down the filling of the cistern by quite a bit - despite being a
full flow type.

You can, of course get a right-angle connector with a built-in service
valve. It might be worth fitting this if you have to replace the
connector anyway and there isn't a SV to start with.

--
Frank Erskine