Rachel needs the room not to feel too much as a toilet but as a stylish powder room with coats storage. My idea is to put the toilet and basin on the same wall and to "hide" the toilet behind a low wall, so people don't see it as they enter the powder room. Use existing storage under basin and get new stone with under mounted sink. Tap on wall? Circular ambient lit mirror. Remove all tiles and just tile the wall with basin and toilet. It can be small format tile as it won't get too wet.