Like others here, at first glance I assumed the view of the water was to the east, but then realised from the sun diagram that north is up the page, so I'm guessing this might be in Bundeena? I agree with most of the other suggestions and have a few of my own as well, will summarise here: - the pitched roof dominates too much, I would suggest the new master bedroom suite has a flat room, similar to the new entry; - the garage is too small and can easily be larger, especially wider and the stair could go down the side instead of at the end; - the foyer/entry is too small for a luxury property, really just a stair landing. I suggest widening it to the line of the new bedroom, and also pulling the entry doors out further to give more space there; - car turning space is questionable. Maybe the external stair could flip over to the other side of the entry to give better reversing room, if it is needed at all (3 stairs???); - give more space to the ensuite, less to the walk-in-robe; - give more space to study, taken from bed room; - angled wall (in line with deck edge) in bedroom instead of re-entrant corner would make it more spacious and allow the bed to move forward with better access; - door to laundry from pantry instead of bath room.

answering your questions: change the sliding door to a bench height sliding window and use the salvaged sliding door in the western end of the dining room where the best entry position is for the deck, you MUST have a proper legal drains do not consider anything else...the drain pipe for the garage laundry can be on top of the concrete floor, behind the washing machine and through the sink cabinet and/or under built in storage and only needs a few cms not a whole floor and no stepped up area that you would see or trip over.. the laundry can't be in a separate room as there's not enough space for a separate laundry without compromising the size of the garage...a laundry cupboard 80 cm deep is enough for the washing machine (allowing for the drainage pipe) you could use the old line cupboard to store anything you want but it's not cost effective to change, the entry foyer is already as big as in many modern homes and there's generous flatpac biw space in the small study.... the family bathroom is 2380 x 2370 (ie the old study minus 1m for hall way and wall thickness and, arranged exactly as shown to allow for the wide window there should be space for a bath up to 1800 x 750, vanity about 1200 x 500 and shower space 1200 x 800 and leftover space makes the small linen cupboard with the door deliberately opening towards the shower to use the back of the door for hanging racks for towels and clothes....btw i understood your priority was maximizing separate sleeping rooms and minimising costs...my last plan has five separate sleeping rooms plus the lounge with sofa bed totalling sleeping places for at least 10 people plus the potential for bunks in the garage so you need to decide what is most important and where you're prepared to compromise

We too live in a cold winter climate with our bathrooms all on the southern side and faced similar issues as you do. One smaller bathroom does not have a window so we put in a Velux skylight which provides amazing natural light through the day. This may not be to your liking, especially if you have a period home. We also use heated towel rails and under tile heating (just enough to take the chill off and stop mould) in winter. Although we have a light in the shower recess, a bonus is the large fixed shower head with inbuilt LED, which at night gives the feeling of showering under moonlight. We chose light colours and mirrored recessed cabinets to reflect as much natural light as possible.

I'd make sure I had probably 3 'zones' or options . It is just crying out for a big industrial style centrepiece on 3 or 4 heavy chains , maybe even with 15 or 20 candles . Just as I'm writing this , I'm even wondering how difficult it would be to get 15 shorter stubbier candles and drill out the middles , and thread a cheap 12 volt LED through each one ? The local electrical supplier charges something like $12 for 10 -- you'd have to wire them , but its low voltage so a soldering iron and heatshrink tubing would do wonders . look way more authentic than those cheesy ones with flickering 240 volt bulbs and fake melted wax on shiny plastic bases ! Anyway , that would be my centrepiece , even if you had to use a transformer etc -- drop it to the ceiling line height . Then I'd do a seperate zone -- probably single LED spotlights ( prob in black ) . at least one each beam , some pointing up , some across to the other 'slope' , but also some pointing downwards , because you'll need to look for dropped coins or handkerchiefs or phone chargers every now and then haha . And the 3rd zone would be wall uplights and downlights , because I can almost guarantee there will be times you want light , but you don't want or need to emphasis the height . If its not too late , I'd have them maybe 1.5mtrs from the floor , and the covers in an aged copper or similar panels , and that would match the style of the centrepiece light too . I'd have the spotlights a completely seperate style though -- more modern and plainer , but not ultra-modern , if that makes sense .