Another worry that i would have it regarding the levels of asbestos usually found in wartime buildings. There is a book Aviation Architecture that may give some info. Most towers have developed over the years, the visual control room usually started on the second floor until shacks and ultimately extensions were built on the roof (third floor). A good preserved example is at Mona on Anglesey, but i do not know if that is the spec you want.
They never were designed with energy efficiency in mind, yet i vaguely remember reading in an olf flypast magazine of someone in east anglia doing such a conversion before, sadly cannot recall exactly were.