Hi Bec. I have a Federation home with high ceilings and I just installed a built-in robe in my master bedroom. The door swing lands within the wall-to-wall run. My solution was to install a 2200mm high robe and run a decorative capping all the way round to top edge. Behind the door, I stepped the robe back and installed a wide stack of drawers and open shelves. It neatly fits in behind the swing of the door without needing expensive structural modifications. I don't recommend going all the way to the ceiling where you have the luxury of height. It will shorten the room and you'll never get up there. In my case, the capping provides a lip which helps to conceal things I store up there that I don't use often like suitcases and bedspreads.

having built several guest accommodations including a separate granny flat for our now 92 year old mum (who also prefers to stay in her own home) i appreciate your desire to make everyone more comfortable but my suggestion uses less space than a second bathroom but makes the bathroom much more spacious and will help future proof the bathroom for yourselves as well as making it safer for mum....by rearranging the existing hall, bedroom doors and bathroom you could have a bigger walk in shower with space for a proper shower seat and all round grab rails and a curtain can be easier, safer (and cheaper) than a glass screen, a separate toilet and bigger vanity area ...adding grab rails and wider cavity sliding doors will also make it safer and more comfortable and i personally find the shower seat and grab rails very useful in the shower and toilet and grab rails also make excellent matching towel rails if installed in a full bathroom renovation rather than stuck on later...a toilet with a higher seat and bathtub built up higher off the floor is more comfortable and another idea we found super useful is a two way switch for overhead lights so that they can be turned on and off from a switch beside the bed..excellent for late night visits to the toilet....useful for mum but we now use this option in all bedrooms....i've include simple biw wardrobes for both bedrooms on the north wall to allow more space for a chest of drawers or dressing table, a comfy chair and bedside drawers and, maybe while you're considering improvements opening up the wall between the two small living areas might be more comfortable to enjoy the views

What width are the backing panels on the robe? Sounds like an old dodgy pantry we had where the back panel buckled - it had as much chance of keeping a large cockroach out as it does a small dog lol. So with the backing panel effectively useless, I would remove it completely & start over with the MDF interior wall lining in the above photo so it looks more like a genuine wall that was always there. I would paint the sheet prior to install ... I love these panels & the character they provide but those little grooves are pesky & time consuming to paint with a brush in situ. Best to spray paint it before it is screwed into place. I think it would look magic & at 9mm, should fit snug in your space? If money is no option, consider getting a pro in to rectify this & put the wall in.

I agree with Kate. This latest photo clearly shows that the top cupboards are too tall. The scotia or cornice will work on top sides of wardrobe, but at the moment, you can not put any joinery in front of the top cupboards because they will not open. You need, as mentioned before, to have the wardrobes reduced in height, for any installation to look good.