Our island is 900 depth, 2400 wide, with a sink in the middle (opposite the cooktop), which works well for us. Plenty of prep area either side of the sink (mind you, it's a single undermount sink, about 500mm wide, with no drainboard). If we were going to use the island for actual meals, ours is only deep enough for a person either side of the sink. So, if you're thinking of having the island as a dining area, go to the 1200 depth. Just walk around it to clean it. On the other hand, if the island is going to be for prep, and a place for guests to prop up a glass of wine and chat while you're getting dinner, 900 is fine. Our dishwasher is to the immediate left of the sink, and we have pull out waste bins underneath the sink. We have 1200 mm space from island to the wall side and the range top, and about the same to the other ends. Our fridge, which isn't huge, is in a 900 mm+ cavity which would be big enough for a deeper fridge. It's in relatively the same place your fridge is, and works fine there. Hinges are on the non-kitchen side of the door, so it opens into the kitchen. Cabinets beside it are a bit more in depth, so fridge and cabinets line up nicely. 850 for your fridge seems reasonable to me. I wouldn't put that study where you have it: I think you'll need all of that butler's pantry for butlering type storage. My 5 cents worth based on new house, new experience, absolutely no kids in the equation!

Thank you both very much. You've both put a lot of thought and effort into this, its much appreciated! Its definitely opened up my thoughts and ideas on the space! Its definitely not as daunting as I was thinking and it is do-able! When you look at it everyday you get a bit stuck. I guess I need to weigh up making that study space smaller. It then makes the house technically 3B 2B. But I'm going to have to compromise somewhere for this to work! Its nice to have something tangible and clear to show the builders, so thank you! I might start drawing up something that's a little of both, as I love aspects of both designs. :)

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

Thank you both for your feedback. Yes, these are the agents plans - just trying to get some general ideas. This is my first renovation and first time posting to the forum, sorry for lack of info. I've included the downstairs of the house (agent plans again sorry, but for context). The laundry has already been moved in towards the workshop area and a new bathroom in it's place. The landing of the stairs will open onto a new deck, and the utility area will be two small bedrooms. The house is on a sloping block with the entrance at road level, so want to keep the front door where it is (to the right of the kitchen). All internal walls upstairs are asbestos so we are having this all removed, which will give us the opportunity to install a beam if we were to remove walls and open the space. The space between bedroom 2 and the kitchen is currently unused space, where I think the previous owners may have used this corner of the house as an office and put in a wall before selling (to sell as a 2 bedroom house instead of 1 bed). I was hoping to get some preliminary ideas before we engage draftsman & engineer - we will be removing the existing deck on the back of the house as well as building a new two car carport on the front of the house.