i would probably try for at least 90cm but depends on the size and shape of the room, location of doors and windows and size and shape of other fixtures..can you post a plan of the room?

if you open the door in the middle back against the basin at one end and toilet at the other the minimum space to to consider would be about 90cm x 190cm and use the smallest toilet and basin depths but would be better to post the whole floor plan to see all the options

Thanks everyone for the helpful advice. I assumed my layout would be similar to that of other Californian Bungalows of the same period. It is helpful to learn my layout is reasonably uncommon and I am probably looking for inspiration in the wrong places. It sounds like Dr Retro House Calls and JRED are correct in steering me towards an interior designer. I hadn’t considered that option as I thought I would need a large budget for furniture and décor if going down that path. I’ll give Bigreader’s suggestion a go first and use scaled cut-outs of furniture to play around with furniture placement. If I still need guidance after that, I will look into interior design services. I initially shared your thoughts – Melt in ACT - and was thinking about turning the laundry space into a large bathroom and then moving the laundry to the small bathroom. Ultimately it was going to be too expensive… and seeing as I have young boys who get every item of clothing they wear dirty within 5 minutes of putting it on, it will be a bit of a luxury to have a big laundry. It's an idea I might revisit in the future though. Oklouise, I love all your ideas and suggestions and am really grateful for the time you’ve taken to respond. The floorplan you’ve put together is super helpful. I was bummed about the lack of space for an entry set down area and would have never thought about moving the bedroom door. I will definitely look into that. Good memory siriuskey- I did previously post about this house and I received a couple of good suggestions (including advice from you) around maximising kitchen bench space with a kitchen island and adding a storage wall near the small living spaces. I felt the advice sought in this post is sufficiently different to justify asking a new question about whether there are resources I may not be aware of and if people have ideas about the floor plan as a whole, including spaces I had not previously asked about. I’ve got lots of new ideas and really appreciate everyone taking the time to share their advice. This is a great forum/ community!

for the banquette to be wide enough to lay on it would need to be at least as deep as a narrow single bed which makes it too wide to sit on comfortably without a very thick back rest or a giant pile of cushions to clutter up the space...why not consider a back and sideless freestanding daybed so the primary purpose is laying down and the sitting to dine is only short term and doesn't need a backrest ....this example or similar with taller legs would be a simple economical way to add the day bed feeling without expensive built ins and two along the window wall could look quite inviting with a simple throw and scatter cushion