As LesleyH has noted but you can make it narrower to 800 but this becomes way to small, for me anyway. If you're pressed for width 900mm would be an acceptable compromise. Having said that 100mm makes a big difference to a small space but can have little effect on a larger one. The 1500mm length is to be able to fit a cavity slider as this about the about of room they need, but also at minimum 1500mm it allows the occupant to use the space comfortably.

what size is the billiard table? you need about 1.5 m all around the table free of other furniture for using the pool cues but the bar area will mean that the table is pushed to one end of the room so the ceiling feature could be over the table or cover the whole room with a border all around ..usually depends on budget but instead of a tray ceiling what about a raked ceiling with a gable roof instead of the hip roof

hi OK Louise thanks for the dimensions. Ive also heard alternative interpretations - 150mm clear on each side of the loo for elbow room and 700 clear in front of the bowl. The toilet Im looking at is 400mm wide, and 660 long. That means a 700 wide and 1360 long could be the bare minimum. That's why Im wondering if i can push it to say 1300 long (ie 640 clear in front of the toilet) I realise you've provided best practice, comfortable and aesthetic layout. However Im just looking at functional, and am willing to make a compromise in this area to free up space elsewhere. Is there an Australian standard or building code that needs to be complied with, that you're aware of? TIA

Your powder room is a bit too cosy for an inward opening door. I would steal a bit of space from your bathroom. You need to be precise about your toilet pan measurements - the toilet symbol shown by the draftsperson may not be an accurate representation of the size of the toilet pan that is selected. In these types of situations, millimetres are crucial. Best of luck and remember that God is in the details, and never assume that others have checked the details. Dr Retro of Dr Retro House Calls and Dr Retro Virtual Visits via Zoom