For those still reading this thread. We just recently completed a bathroom reno in almost identical sized space though turned the other way. A lot of reflection in the photos sorry but there is a lot of glass and mirror. A cavity slider, while an added big expense, made the whole thing possible. To create the space I used the adjoining separate toilet room for the 1200 x 900 shower and shallow tall cabinet on the left and gained a closet in the hall outside with the rest of that corner. I also recessed the towel rail which helped give room to the shower entrance and not stick out in front of the loo. Wall hung vanity and toilet. Porcelain wood planks on floor with underfloor heating and also used in shower base. Excuse the towels, they are not my normal ones ! It was a big decision about joining the rooms and whether to keep the bath / shower but I think it paid off. There is just the two of us and it's a real pleasure to use and no longer feels like "standing room only"

something like this may suit without altering the plumbing too muchor this arrangement adds more privacy from the living area, has the bath in the main bathroom, a bigger shower in the ensuite and more space for mirrored wall cabinets and a fixed "window" above the mirrors could add extra daylight between the bathrooms

@AAB That Ikea one looks like it has good dimensions from above, but I think you'd find 20cm too shallow to double as a useful laundry tub. If you could find one that was twice that depth… I did encounter such a sink in a long-stay apartment hotel I stayed in recently. The bathroom was fitted out with a combined washer-dryer unit and the "basin" – while styled aesthetically like a bathroom basin and oval in shape as well as rounded in cross-section – was really big. You could have washed a large baby in it! So clearly that kind of thing is available. It did require a fairly deep vanity to mount it in, but that was there to accommodate the depth of the washer-dryer anyway. The only thing with a deep vanity is you absolutely need to mount the mirror on a cabinet to bring it forward, not directly on the wall. If you don't do that anyone who is short and/or short-sighted has a hard time using the mirror for practical purposes such as shaving, inserting contact lenses, or applying makeup. (Yes, I discovered this during my hotel stay too!)

No-one seems to have brought up what , to me , seems like the second most logical suggestion ( admitttedly , without knowing the planning rules ) . The logical still seems to be to sell . Failing that , I'd look at extending the study , taking in the courtyard , alter the internal door ( suggestion - a single door on the 'right' side of the existing study doors area ) , add an ensuite ( relatively easy as the existing bathroom is just through the wall ) , and make that room your master bedroom with en-suite . Move the ranchslider , or add a roof to floor window , to get natural light into the new master , and possibly add a skylight or two above the dining room , as it will lose the ranchslider . Not perfect , but if you go up it will be costly , there are engineering issues , matching materials , new roof , all sorts of logistical problems . 'My' suggestion cuts down outdoor space , and may exceed the building to land-size ratios , but its so much easier building , engineering , roofing , plumbing and materials matching wise , gives you all or most of the space you are after , so IMO way more bang per buck . Having said that , only you know your priorities , budget and what you are happy to give up to gain .