First and foremost - what are your plumbing facilities and where are they located. This may have a large effect on what you are able to do.... I have transformed a bedroom to a bathroom and some creative returns and plumbing were required. Also are you intending to add a toilet?

Thanks houssaon and rinqreation! Funny - hubby has the same 2 door hate! It sounds like I'm being outvoted on the shared ensuite idea. :) We've actually been set on both the configurations you suggested, we moved away from yours houssaon because we really wanted to keep a closed off office space (and hubby built the front deck and landing already for the door at the end of the hallway!). And I don't know why we shifted the door on the bedroom back to the same area, I think it was about having easy access to all the kids bedrooms. But maybe we should shift it back as you suggest rinqreation. Joice, the door at the end of the hallway is the front door, the entrance closest to the street, that you would come to first if you were a visitor. Not totally necessary, but we reinstated it before we decided we wanted the entrance up the stairs (middle bottom) which would be under a carport. Thanks for all your input!! It's really helpful to have some unattached opinions. I'm keen to hear from anyone else on the shared ensuite or 2 door hate question! :)

Third vote for getting a professional involved, but i'll still offer my layman's suggestion given that you're just soliciting general ideas at this point. If it was my space, I'd switch the bathroom and the laundry room around, keeping just one of the walls currently enclosing the toilet. Its hard to estimate precise measurements from the drawing, so it may not be feasible, but here's what i mean

Hi, Thanks for the response. :) I am following CCC Residential Suburban and Residential Suburban Density Transition Zone. It seems you can build 1m from boundary without having a window facing the boundary. I thought it seemed close, but if it gives me more space on the sunny side of the property then I'm happy. I wasn't sure how worthwhile it was me building interior/external walls into my design. I think a real draftsman would only use my dimensions as a guide and bin my project designs. I've only used the boundary line to design the entire thing, then used some Objects to give a visual guideline.