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.

This looks like an acrylic

http://www.screwfix.com/app/sfd/cat/pro.jsp;jsessionid=CDO1JMQMRQS3GCSTHZOSFFI?id=9905 8&ts=42578