How do I bathroom / kitchen / extension? etc.

I have one from InFrame. They were fantastic, the room is solid as hell, and I'd recommend them in a second.
Currently the temp is just about perfect, but it was never cold in winter.
I'm probably going to put A/C in, and definitely will put a green roof on top, which will reduce the thermal mass of the black material massively. (Just need to get round to it!).
Learning points:

1. Get that double glazing with internal blinds.
   
2. Put a secondary window in somewhere for through breeze.
   
3. It is the best place in my house to work, use for the gym, and work on bikes.