re the single glazin.
I'd say thats strange. Why would you not double glaze the whole section.
Double glazing is a form of insulation, to only havf do it is not ideal. Maybe just to reduce costs? Ouch - did it just increase for glazing costs?
Heat rises, in winter this area will be loosing heat big time.
My upstairs section gets up to 25 degrees in winter throuygh solar warming, , yet come sundown- you can just feel the cold comming through the glass.
My double glazing is going in this winter.
Steve