Personally I wouldn't use plywood , firstly op had never mentioned whether light is needed or not....I suspect it would be advantageous. I also wouldn't use Georgian wire ...hate the look of the stuff. If there is a need for fire rated glass ( blocks of flats and the like ) , I'd use 7mm...
Look up how to toe and heel a door also
You say they were open in and you've turned them around... what have you done about the built in drainage? A upvc frame is cellular and the outer section is for drainage , you should really block all drain holes up internally( I hope it was face drain...
If it's just height you need then no you don't need to remove the cover , just adjust the back Allen bolt. However if you look at the door and notice that the leading edge of the door is lower at the top than the hinge edge , then you will need to access behind the covers of the top and bottom...
Georgian wire cast ( obscure) is no longer deemed a safety glass and there is a shortage in the UK presently . To be honest toughened glass is your cheapest option ,would have to be ordered to the correct size though as once toughened you can't cut it.
Laminate is good if you get 6.4 ( or 6.8...
Totally agree Crank , it is something that definetly requires practice, even after 20 odd years I still get it wrong occasionally lol and I see why he did it but to say ' that's how hinges are ' is absolutely ridiculous!
Post a picture up of the inside of one of the windows in question , close enough to we can see the edge of the glass and frame but far enough way to get asmuch in as possible. We should be able to tell you from that I'd it's internal or external
That cement/mortar that's in those gaps will fall out overtime. Personally I'd have put a clear silicone and then fixed a small upvc quadrant over it to make it look tidy
Is the wood actually rotten? Replaced a lot of glass units in these over the years and yet to see one that the wood is rotten despite being black like that.