The house looks very livable. I love that you have concentrated on creating one nice bath with separate walk in shower and a windowed tub! Since you have already thought of it, I'm going to assume that the attic is for future expansion and cannot be adapted for use as the current "away room." We are also in the process of designing a small house, and we've designated our study as the "away room." Ours will open off the dining room. If you switched the locations of the Study and Bed 1 on the same side, you could put french doors or an extra wide door with etched or decorative glass from the hallway into the right hand corner of the study. This would give you a really long diagonal view through the lounge and out the french doors, and from the lounge through the study to the window at the far end... The study window should be increased in width to match the neighboring window in Bed 1, and it then becomes ripe for a small window seat, either a clip on bay bumping out, or a "built-in" bay using narrow built ins on either side. Or both: build "in" for now, putting file cabinet drawers under the window seat, and angled corner units in for storage, and add the bump out bay later when you know whether your offspring would prefer a really cute desk, or a window seat, or a bed nook. You would, alas, lose the door from Bed 1 into the bath.... but honestly, there are lot of doors into that bathroom already, and that one has substantial collision potential. It might be best to make the single access point that door from the laundry. Either a glass panel set high in the bath room doors or a transome would make it easy to tell when someone is in the loo. Other ideas would be to split the nook under the stairs, so that half the depth opens to the lounge, and the other half to Bed2... with the wall thickness, you probably get close to 600mm or 2' on each side. Add a deep bookcase or other built in, and you're easily at a depth that makes both spaces very tucked in. Lastly, if funds allow a shallow bay window over the kitchen sink would visually expand the kitchen, particularly if you could arrange it so that the counter runs right into the bay.

I don't think that you will have a problem without building a study........ The extra garage space will be a valuable asset...........and can do double duty.....

I recommend having the TV in a separate well-insulated room if you're having a great room/open floor plan. We combined a play room/media room and put french doors on so TV is visible from great room/kitchen, but noise is contained. Also, love having hand-scraped distressed wood floors that have withstood our kids and dog. Quartz counters have been proven crayon/paint/marker/anything-resistant. A mudroom with cabinets helps contain backpacks and coats by entry (ours is by garage entry since that's how we get in the house). Maximize built- in storage in every room--it's nice to have the option to store away all the toys/school projects/art supplies where they're used and played with. Consequently, we also put in a walk in pantry to store packaged foods and craft supplies. Can keep going, but these are good to start with. Goodluck!

You could reverse the layout of the ensuite, and have the door to it through the walk in wardrobe (so you would only have one door coming off the bedroom). If I were you, I'd consider swapping the positions of the ensuite and wardrobe, so the current ensuite door becomes the wardrobe door. That way you could move the bed to the east (right), and you would have room for a seating area in the north west corner of the room (as your bedroom looks huge!). I'd also add a window on the small bit of north facing wall in that room; you already have corner windows in the living and another bedroom, so you could match those in style. Personally I don't particularly like the current layout of the main bathroom, although I can see the reasoning behind it (i.e. vanity at entrance, toilet hidden behind wall, window above bath). I think it might work better if you put the shower in the corner where the bath currently is (i.e. beside the toilet, opening to the west), and the bath on the same wall as the vanity. You'd have to move the window, of course. Alternatively, do you actually need three toilets? You could remove the toilet in the main bathroom, and you'd have room for a freestanding bath and/or a bigger shower. You could consider stealing a bit of space from the kitchen to create some storage at the entryway. I'm not sure where your garage will be, but it's really handy to have a designated place at the point of entry for all the stuff you tend to dump when you first come into the house (schoolbags, coats, mail etc). Overall, I think the layout is pretty good, but you could potentially lower the build cost by making it all a bit smaller. It's really worthwhile taking the time to figure out just how much space you actually need, and where you need it. For example, if it were my house, I'd take about half a metre off both the east bedrooms (so the house is shorter from east to west), plus I'd make it smaller north to south by slightly reducing the size of all three bedrooms, and making the kitchen a bit smaller (so the hall cupboard lines up with the back wall of the small living room). But your priorities may be completely different from mine!