subject to correct measurements my suggestion includes extending the kitchen into the old laundry and creates a new laundry next to the study with hallway access for a re-arranged bathroom but we need correct measurements to identify positions of existing toilet, taps and sinks to be more precise.Does the existing laundry have external access? do you want/need external access for a new laundry? do you want the kitchen to be open to the living and family rooms or would you prefer separate rooms? is the under stairs space already being used for walk through storage? what about access to the garage from the front entry?.....with correct internal wall measurements we could make more specific suggestions but your plans don't show or we can't see details of existing rooms

This looks great. Our bathroom had the same layout, but we managed to fit a much longer bath and a toilet in by moving the vanity from under the window to the left hand wall, putting the longer bath under the window, putting a toilet where the bath was previously and leaving the shower in the same position. We also changed the door to a cavity sliding door to take up less space in the room. We had a similarly awful 80s renovation in ours too, and used the same sort of wall tile

Sorry family house needs at least one bath. We may not need ours often now kids are teenagers but my 16 yo still has them sometimes as does my 18 yo son and when you come home after a hard day riding it’s a godsend. Not to mention a future young family.

One thing to watch out for with top mounted basin bowls is what your wall covering/splashback is behind it. If you are doing a mirror or tiles down to the vanity, have them installed before the bowl, otherwise sealing the mirror/tiles with silicone after is really difficult and you risk getting a poor seal where it is most critical.