The floor drops about 25mm from the door to the window (opposite the door) and the joists run from the door to the window.The distance from the door to the window is 1.98m so I guess the whole floor will need to be pulled up to level it properly. I was intending to use a circular saw as I don't have a reciprocating saw, but this would then leave an edge of board around the wall the same width as the guard on the circular saw.