Your mockup scheme is similar to our master bathroom we just completed - photo below. I know you mentioned storage being a concern - our mirrored cabinet has offered an amazing amount of storage in a very small space and also helps bounce light around. I was worried about black taps etc too so we kept chrome fixtures but added in a matte black candle and black potted orchid to create a similar effect which we can change out later on. Our floor tiles are dark but because they are semi-polished they actually bounce around a lot of light and don't make the room feel dark if that is a concern. We also have a huge fiddle leaf fig in the corner (not pictured) which adds a really nice feel to the space - a plant like that could help bring in the outside greenery in your bathroom. Instead of the storage tower you have to the left of the vanity could you do say some floating wood shelving, possibly with baskets added for more hidden storage? You could also bring in the 60s theme with what you displayed on there eg. photos as you mentioned? In regards to the window - a previous house we lived in had a window at about shoulder height in the shower - as well as letting in heaps of light it was amazing for storing toiletries etc!

Thanks everyone. Nik Star I did get some colour swatches for navy, but then didn't have the courage to go ahead. Think I will have to just be content with some navy towels.

I think oklouise plan with bath on the far wall gives you the most space, as well as giving space for towel racks. With a bathroom it's not just about the look. You have to think of the practicalities, especially with kids involved. If you can do the shower with just a sloped floor to the drain, like a wet room, and avoid the glass walls, it makes cleaning so much easier and looks more spacious. Perhaps it is worth considering just having a shower, if the kids are old enough and you are not planning on selling. You could have a really big double shower with a bench. we ditched the bath in our bathroom and haven't missed it at all. We also went for a floating bench vanity with a large mirrored 'medicine cabinet' above for storage, as we didn't need much. If you need the storage a floating cabinet, as suggested, would still increase the feeling of space. And you could also still have the mirrored cabinet above. We found custom and even ready made mirrored cabinets to be very expensive, and eventually found a lovely two door 1930's kitchen wall cabinet at an antique shop for less than $200. We took it apart, cut it down so it was shallower, put it back together, sanded and waxed it then replaced the glass in the doors with mirrors made to size by the local glaziers for about $60 each. It is even more beautiful, copes well with the moist atmosphere, and holds what we need. We love it, and it is a great talking point with guests. And we have a separate toilet too, which we just find so practical.

@oklouise thanks for measurement suggestions, good starting point with so many choices available. About the bath, we thought just a freestanding, or back to wall bath, would take less space compared to drop in bath. But it something worth considering with the suggested layout. Also, the bathroom entry door would be sliding cavity if that helps. @differentways thanks for a suggestion that we haven't really thought about. We have considered a smaller Japanese style deep bath, but obviously this would not be practical for kids. Just to make sure I understand your concept, you are suggesting a purpose built bath which will be about 2570mm (including the ledge), husband thinks this is very generous :). My husband and I can't find a photo of something similar, do you have a link? Are you suggesting the sides of the bath to be a lower height compared to standard bath? I like the idea of a ledge, would definitely make bathing kids easier. About the position of the ensuite, do you mean placing it outside the bedroom area so it can be accessed by others? We have discussed this, still part of ongoing discussion. If need to we just have to move the bedroom entrance door. I have attached a google earth view.