You need to post to scale floor plan of the spaces you are talking about For this forum in feet and inches probably.All the meaurements clearly marked and both spaces with meausurements clearly marked . All windows, doorways , where the doorways lead and the plumbing if this is a renovation moving a toilet can be a big deal.Why do you have a doorway from the hall into the master bathroom or is that bathroom shared ?

Hi Patricia, can’t you see the image I posted of the scale drawing?

That is not a to scale plan it shows no meaurements except the one across the top

Ahh yes, I thought it was clear since title was 5x5m but have annotated this version to help. Whole area in pink is 5x5m, there is nothing there now except a flat roof so layout is fully flexible. Blue marks where windows could go otherwise skylights are an option. The two potential access points are marked with arrows and ‘option 1 or 2’. Drainage for the en-suite would be easiest on the left hand side. Hope this helps.

Since you are only in design phase… I would consider making the old bedroom space the master bath and proposed new bath space a large walk-in closet. Doing so keeps the bathroom noise away from sleeping area.

Thanks, that would be great although ideally looking for an option that means I can keep the existing rooms as bedroom and office.