You should move the SW corner in the kitchen to the hallway. So the hallway wall is aligned, and the kitchen unit is also installed. Then I would relocate the tall cabinets in the kitchen to one side; the door area is bad, maybe to the exterior wall? That way you have more freedom when it comes to furnishing the office room. Then I would strongly avoid using an open staircase as a cloakroom space. Dirt falls from open steps, and it always, always, always looks messy and will always be that way. It’s better to wall off/cover the bottom of the staircase, put in a room door and use it as a wardrobe closet; you have space for that if the corner in the hallway disappears. Regards