If it’s possible to move the toilet I would put it in the corner where the shower is now, large vanity single or double in the place of the toilet and double shower instead of existing vanity across the whole wall. I hope you can picture it. Some people here might be able to do the design I am not that smart.

The laundry has 2 doors , which means 1/3rd of the shown space isn't useful . Kate has suggested having the external door out from the 'gap' , which makes sense , and I assume a window above the tub or similar for light ? Having the external door opening outwards ( no matter where you position it ) means you get more interior space too , but also a bit easier to seal for wind and rain too . But if you moved the laundry wall 'right' , and had an outwardly opening door from the laundry to the WIP 'foyer' ( the space outside the WIP can't really be used except for access ) you'd have a smaller laundry footprint , but be able to have more storage , maybe a drop down ironing board etc too . But also , I wonder if you'd be better to make the WIP effectively 2 parts -- one that gets the natural light from the glass door , and then move the wall further in so the existing one that is darker for light sensitive items ? It may look less tidy , but conversely the existing design is going to mean the pantry will always be quite dark , unless you add a skylight or similar ? just a thought .

a rare chance to use imperial measurements but adding suitable scale sized furniture will help identify the best sizes for rooms, three equal bedrooms will be more useful for long term extended family use with the reading room used as a play and bunk room and the bathrooms need to be bigger for your son to be able to use them with his walker including easy access from outside

Thanks Dreamer. Hubby has a real hatred of bar-height eating. He was emphatic that we would not have stools to eat at the island. It had to be regular seating at table height. We will have a small table in the square space but the space there is quite restricted. It will be just for the two of us. I agree with you about the drawbacks of banquette/bench seating, but as it will generally only be for occasions when our daughter and her family join us for a meal or those rare occasions when we have guests staying over, I think I could live with it. I guess it depends on the size and configuration. It might be able to be set up so that two people sit on the bench and get in from either end, then two sit on the other side and two at the ends, as you have drawn it. It's just a question of how much width is needed, because I don't think 3m is really enough for a regular table and chair arrangement? I'm quite content, though, for the seats on the left and at the ends to be moved there from elsewhere for the meal and then put back afterward. Only the seating on the right needs to be permanent.