Is it on a plinth of any sort? and could that plinth be removed ? On some old Victorian/Edwardian chests they can be screwed to the carcase.
When we moved into our present property, I had to cut an inch off the plinth on a mahogany chest of drawers, just to get it up the stairs and into the bedroom.
And we had further problems, when the mattress on our double bed was replaced. The old one easily came down the stairs, but the new ,firmer one, had to be bound with webbing clamps, and tortured into a curve ,to get it to fit up there.
Regarding passing it in through an upstairs window, This seems to be a feature allowed for in lots of old cottages. I once made some windows for a cottage in Norfolk, which comprised three sashes fixed side by side in a frame. The central sash was screwed in place, with the outside ones hinged, and rebated, to close against matching rebates in this central sash. The purpose of this design ,was to allow furniture to enter through the window, when the central sash was unscrewed. Some of the neighbouring cottages , had even wider windows, with greater numbers of removeable sashes, which would have easily allowed for a double bed to pass through.