I have just taken a couple more pictures (excuse the untidy house) from the stairs. As you can see it's an open plan area that isn't that big but very high ceilings also in wood (Macrocarpa) with dark wooden beams. The house is surrounded by bush so quite a dark house. I initially considered a darker wood similar to the beams but not sure if that will make the house appear smaller / darker...I'm really not sure what to do!?!?!? Thanks

See the edging around the top of the tile in the shower? Can I do that to an acrylic wall panel? (I hope this picture works?) Eclectic Bathroom by Chestnut Hill Interior Designers & Decorators MANDARINA STUDIO interior design

Bring the window down to meet the cupboard. Really lefty47 was right about not drawing attention to it. It is a source of light ,,, so no need to clutter it up. But if you took the colour out and painted the top of the cupbard to match the wall it ceases to draw attention to itself. Just because it is a horizontal space does not meant it needs something put on it. Note- With the cupboard being white, it also draws attention to itself … perhaps take that to the wall colour too and lift the pendant a smidge. So your pendant is the feature there. The cupboard … do yo need it? One way to remove what you are calling dead space is to get rid of the cupboard.

Actually, just reread a bunch of the tile places and they all say not to use in shower. Bummer - that's out. However would still love ideas on what to do around it and if anyone can think of a way to update the acrylic walls? Or maybe it won't be as bad with new fixtures/shower curtain in better lighting... fingers crossed... just trying to get ideas together.