Hi Pummers, no architect worth that title would ever just provide a default plan. The architect's JOB is to discuss your needs and wants with you and work that into the design, often through a number of revisions until you are satisfied. If he/she doesn't do that, speak up about them not giving you proper architectural service. I know about the problem of space for towel rails in a small bathroom. What I have done in such situations is to fit 2 towel rails on the back of the bathroom door, one at 900 and one at 1800 height. That usually works very well.

my suggestion are based on location of existing doors and, without moving any walls, there's just enough space to have an ens, separate dual access powder room and small wiw and biw if the master bedroom is in the smaller room and the French doors open outwards for more walking around space.. adding an internal window to the wiw will give also add light and view from the wiw

if your long term plan would be to extends at the back i think reconfiguring the existing family room or bedrooms for a generous master suite would be better than removing the wall at the front to enclose the balcony ...the front wall supports the main roof and there would need to be expensive alterations to add suitable support for the roof, create a new floor, line walls and ceilings and the balcony floor and ceilings are probably lower than inside and/or don't meet current building standards to be used for an inside room and the cost would not be worthwhile for such a small addition when there are so many better alternatives... the house has good proportions that suggest many different options and if it's in good condition in a good area for a good price then you could live comfortably until you decide on best improvements and here are some other variations..

We have just finished a 3-year renovation with some similar issues to this! My suggestion for a cost-effective ensuite would be where I have drawn in green. As it's in line with the other utility rooms it may be most convenient for plumbing. If you put a high window in with the toilet under the window, a small wash basin opposite the door (use a cavity slider door) and the shower closest to the passage then you should only need 1.2m internal width to fit it all comfortably (depending on size of basin or vanity). You could possibly fit a cupboard or small wardrobe between the shower and the passage wall as well to help with noise reduction. The room would need to be about 2.4m long. Hope this makes sense and is of some use!