On Sat, 29 Nov 2008 17:49:19 +0000, Lobster
wrote:

Thanks for the suggestions folks.
I'll try giving the tubes another clean and then try the 'deep clean'.

Actually several years ago it started to leak. I couldn't work out
which seal was the problem so lived with it for a while (catching the
drips whenever it was used - wife wasn't impressed!)
Some time later the leaks stopped - I realised later that something
must have reduced the water flow - but it was still cleaning okay.

I figured it had now reached the final stage of deterioration.
But I'll give it one last chance.