[quote author=WJOHNM link=1085417575/0#2 date=1085420839]
how about a new double glazed unit for the patio door with the hole pre cut in the toughend glass.i have seen this done before for extractor vents etc.
might be costly though.
john [/quote]
I had this done. Used a clear polycarbonate cat-flap. It works great and is very inconspicuous.
Trouble is, big patio doors so the replacement panel with the hole was expensive, cost £400 all in.
Symo