Here is the floor plan

The size is fine for dark colours of that's what you prefer. A freestanding bath is more modern but you want to make sure there is decent access for cleaning etc.

A bath like this would be good
https://gwa-prod-pxm-api.s3-ap-southeast-2.amazonaws.com/items/original/40916_LU4WFW Caroma Coolibah Contemporary Back to Wall Bath 1400.jpg

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I cannot access the link can you please copy it again

For the resale you think darker colours are better or brighter?

https://www.ebay.com.au/i/303330104501?chn=ps&norover=1&mkevt=1&mkrid=705-139619-5960-0&mkcid=2&itemid=303330104501&targetid=958835004637&device=m&mktype=pla&googleloc=9071947&poi=&campaignid=9772794666&mkgroupid=99377633506&rlsatarget=pla-958835004637&abcId=1145981&merchantid=9743792&gclid=CjwKCAjwp-X0BRAFEiwAheRuiwiW5Ia7vjuRVivUkaGcymF1kxMpSUPZhPpOcXWNBj0eRw7HfcmY8BoCuuoQAvD_BwE

that might work

I just meant a back to wall bath which isn't built in

Clean, well planned and functional bathrooms, would be good for re sale of property.
Colour trends change, but the need for a functional space, never will.

Go with what you love! For the separate toilet use the same floor tiles as for bathroom, if tiling, and then just wallpaper the whole space. Find a statement mirror..that's always gorgeous. I always tell people make the shower as big as you practically can. Possible you could consider moving vanity along wall as you look into bathroom to the left. Shower to the right and bath under the window..unsure how much space you have. Make sure you have good lighting in a dark bathroom. Once again good large mirrors with help bounce the light around. Good luck!

Can i just tile the floor of power room and use painted plaster or wallpaper for the walls or this would look cheap and not long lasting?

Ros213 GI, I think it depends on how much you want to spend. Both options can look beautiful. I also saw on this site somewhere that people had used a stencil to paint a wallpaper like wall (it was in a lounge room but looked great all the same). I tiled to the ceiling in both small bathrooms that I have just renovated....tiles and tiling work out quite an expensive outlay. However, I was doing some dreaming the other day, and went through a home that I can't afford, as per link.........it's bathrooms gave a sense of luxury and beauty and yet very little of the walls were tiled....I think it all comes down to good design in the end....https://www.realestate.com.au/property-townhouse-qld-grange-133034482

I personally think that very dark colours on the walls will divide buyers ...people will either love or hate, but a tasteful lighter bathroom will appeal to most people...eg. love or like...and can happily live with it for longer.

How do you want the bathroom to make you feel? Would you rather moody and sensual or calm and serene?

Do you like your tub? I do :)

I guess calm and serene. So do you suggest i keep my tube? It’s basically a jacuzzi with a motor pump on the other side of the wall

If you want calm and serene, go for light colours with low contrast and ample light.

I think its great! I understand the edging is a little out of date but I think if you were to choose a tile that had some character it would merge in and look lovely, something like a terrazzo maybe. I'm loving the round tub, I think we will be seeing more of these very soon.

My question with the dark tiles is that it is really moody and would need to be reflected at least in the master bedroom. So if you normal decor is light and pretty then keep with that style. Corner baths are dated and take a lot of water, but if you enjoy it then keep it.
Powder room, taking the floor tile up the wall to the window sill behind toilet and as well as tiling a splashback on the sink would be ample tile and leave rest painted, with tiled skirting of course.

Rose213GI I personally think that the corner tub look is a bit dated, but you may get some designers to give you better advice than me. To me it says 90's.

Thank you all for wonderful comments