On Thu, 20 May 2021 14:20:53 +0100, Fredxx
wrote:

On 20/05/2021 13:59, MM wrote:
The cistern service valve is very slightly weeping and so will have to
be replaced. But in order to remove the valve I shall have to cut off
the ferrule at the compression joint end. As it is unfeasible to
actually saw through the ferrule, the usual approach is to saw through
the pipe just past the ferrule. But then the gap between the cistern
inlet and the new service valve is likely to be too large.

Ferrule? Do you mean olive?

It is normal to simply connect the new onto the old pipe with the old
olive, or if using a fibre washer, same nut with a new fibre washer.

Turned out that a new fibre washer was all that was needed. I bought a
packet of 10 for about 50 pence from local DIY store. I'm going to
keep checking it all afternoon, but so far no drip after an hour.

MM