The original one had broken, so a replacement has been bought. The
original had just the one ribbed soft sealing ring, the replacement had
two, but no instruction for assembly.

One of the rings has a ring of ribs around it and will fit above the
hole in the sink, or below - the other is completely flat slightly
thiner and its internal diameter would need to be stretched to fit
above of below the hole in the sink which would make assembly
difficult.

Is the latter seal just a spurious part?

Does the ribbed one fit above the hole or below?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield brought next idea :
The original one had broken, so a replacement has been bought. The original
had just the one ribbed soft sealing ring, the replacement had two, but no
instruction for assembly.

One of the rings has a ring of ribs around it and will fit above the hole in
the sink, or below - the other is completely flat slightly thiner and its
internal diameter would need to be stretched to fit above of below the hole
in the sink which would make assembly difficult.

Is the latter seal just a spurious part?

Does the ribbed one fit above the hole or below?

Sorted...

The thin flat one must have accidently fallen into the box. The
manufacturers web-site only shows the thick ribbed seal.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk