In article , says...
Anyone know where I can purchase some of the rubber seal for the double
glazed windows and doors.

TIA

PVCu windows are fitted with "seals" and "gaskets".

They are available in a huge range of profiles and sizes.

The only safe way to obtain the correct replacement would be to contact
the original window manufacturer.

--
Ziggur
"S'ils te mordent, mords-les"