[Mr Mole]

That normally pushes onto a bead when you put the glass in a green house.

This particular shaped one pushes up into a slot and is proving rather difficult to find.

It’s a lean to aluminium thing but the chap has no idea what make.

Hopefully a picture will arrive below this showing the end section.
  Anybody any ideas??.

[Lardman]

Have a look here
http://www.sealsdirect.co.uk/bbCMS/listDepartments.asp

I bookmarked the site a while back .. thought it might be useful.

[Mr Mole]

Thanks’ for the link “Lardman”.........will study it later. Prob drop them email with picture.