Treat the whole window zone as one working assembly
Measure the opening, recess depth, wall return and space above the frame. Then operate every sash, casement, handle, shutter and restrictor through its normal movement. Record radiator position, vents, sockets and furniture that must remain. A blind sized only to the glass can foul a projecting handle; a pole placed too close to the ceiling can make rings or headings awkward; full curtains can cover heat or obstruct a door beside a bay. Photograph the entire elevation square-on and add a side view that shows depth. Decide whether the purpose is privacy, light control, insulation or decoration because each changes the preferred position. This survey turns an attractive product into a fitting that can actually work without sacrificing window operation or everyday access.

