Personal choice but galley kitchens for example use around 1000-1200 in a bog standard home. The kitchen should (personally) be in proportion to the rest of the house, your life style, family, etc.. The only rule with layouts are there are no rules to layouts. It's just what feels right or look's right to you personally.

Hi Jane, I didn't think the Study was a bedroom that's why I suggested changing it to the laundry. He would have a bigger bedroom using Bed 4 The deck at the front was a great idea another place to sit.as the house is already quite pretty The garage is as you say ridiculously narrow and I consider having a driveway with a garage at the end a waste of space anyway. The one good thing is that it is on the boundary, I think so gives you maximum space. are you able to bring a carport forward towards the street, just add that to your plan. Your neighbors aren't likely to complain about anything there as it's also on their blind side. Is the garage under the same roof as the old extension? Who uses the other 3 bedrooms as there's only 3 kids, would you agree to move the bathroom back into bedroom 4 and keep the powder room and linen cupboard where I lastly placed the family bath? Sorry but I'am trying get rid of "The toilet block" across the end of the courtyard. Or would you consider adding the laundry into the garage along with your WIR and possible study.

just realised that my suggestion has overlapped with Dr Retro and i agree that you should be able to have (from left to right) a 900 wall cabinet with three equal doors, a 900 wall cabinet with the 900 wide rangehood and three equal doors and a 600 wide wall cabinet with three equal doors ie 8 x 300 wide doors with the left hand side of the range hood wall cabinets lined up with the 900 corner cabinet BUT is there any special reason why the wall cabinet for the rangehood was suggested as 1000 wide?? if so, the same concept applies ie left hand wall cabinet would be 850 wide with three equal doors, 1000 wide range hood cabinet with three equal doors, right hand cabinet 550 wide with two equal doors..ie 5 doors about 270 wide and 3 doors about 330 wide above the rangehood but aim for the 8 x 300 doors.. the cabinet maker should allow for all the necessary clearances and fillers to create a uniform appearance

No, and it would be better. Left as is, the people that sit at the island, will be sitting in the walkway, and the space in the dining and lounge, being only 4340 wide, would be compromised. It is not just the width of the island bench, you need to also take into account the room taken up by people sitting at the island. Could be, Maybe another 500mm into your lounge and dining area. Shown on your plan as theatre?