The size of our master ensuite is fixed at 5190mm x 3000mm, as is the entrance door position fixed.   The freestanding bath will be 1800mm X 870mm The basin will be wall mounted - 1200mm wide The toilet will be wall mounted Shower will be ceiling mounted monsoon/rainfall shower head and a normal wall mounted hose type one.   Below is the current layout, however I'm not sure if it's a bit boring and will look sparse with so much space in the centre.