Trevor,
Thank you for a very interesting and timely article. My windows are out and I plan to replace them over the winter. The windows I removed measure between 4.5mm and 8mm, and that was after removing 50 years of mastic and silicon. A89’s coach roof is 6.6mm thick around the windows, so I was hoping to buy 6 or 8mm Acrylic. Which would you suggest please?
You mentioned that you re-tapped the holes in the inner frames to a slightly larger metric size.Would that be 5mm?
How long were your new stainless steel screws?
Thanks again for all your advice.
Richard