Liam wrote:
Whats the best available material around for sealing a replacement
pane in a single glazed wooden sash window? Used Linseed Oil Putty on
the last one but that was five years ago.

Linseed oil putty sets rock hard over time and is the major cause of rot
in the lower part of sliding sashes. The thicker layer used in casement
windows has a better chance of survival but basically it has nothing
going for it compared to acrylics. They can be overpainted within a
couple of hours and stay flexible. IIRC Vallance do a universal sealant
suitable for glazing