thanks Mike, didnt lookat the real old school flat felt stuff! I'll give it a go but I'm still running (yes Frank after 25 years ) 5mm acrylic windows so this might be to tight??
just braved the cold winds and taken a closer look at the chrome frame, it has a return on the inner edges, is this to hold the flat felt trim in place.....either I forgot about that or never noticed! probably both!!
Nigel, yes, the felt has to fit inside the lip and has to be trimmed down from Wollies standard size. As Frank states, I used the 1/8th felt and the standard glass fits fine. Not sure about your 5mm acrylic, though as I can't remember how thick the glass is.