It’s also worth raising the bathroom door threshold by about 5mm from the floor in case the room fills with water (if someone covers the shower drain with a towel, for example). This will keep the water contained.
Replacing fittings, flooring and tiles or repainting walls is a quick way to get a refresh. If your layout isn’t quite right, think about the ways you might be able to make small but effective changes. Rehanging doors or fitting sliding ones is an excellent way to gain space, for instance.
If you do plan to change your layout, measure your bathroom carefully. Note the position of doors windows and any pipes. It might help to draw an outline on graph paper, or use an online design tool.
Be practical and take advice on whether your floor will take the weight of a cast-iron bath, as they are very heavy. If it won’t, then composite or acrylic versions are good alternatives. If you decide to place your bath near a wall or window, do plan plenty of room around it to get behind for cleaning.