I am not the best person to comment on lights but would a few downlights be the go or one of those integrated heat/fan/light things be best in centre. Also a lot of people have task lighting......so lights just above the mirror for makeup etc. Personally too bright lighting while doing makeup sends me into a spin as I look like i have about a month to live! I hadn't thought of approvals for my proposed window - so thanks for that. Must keep that in mind. My bathroom is very hidden and looks nowhere in particular. It is all looking good. On another note my friend got a heated towel rail and much as I hate wasting power it is fab. Our towels seems to stay dampish in uninsulated BV '60 box in Melbourne. Also i would have a look in bathroom showrooms for some ideas too if you have any handy. Or buy a bathroom specialty magazine. It is going to be so nice this bathroom. What tiles etc?

If you plant a flowering creeper in your pots and guide it using a piece of string.... You can grow yourself a piece of art. The creeper will always follow the string.

Thanks for all the input! Lots to think about here. To answer the questions, to the right of the door is a bump out from a linen cupboard in the hallway - we won't be moving or resizing that. There are no windows (all walls are internal). Yes, we were thinking of a 'ladder' style towel rack to use some height. The doorway is 700mm and the toilet wall to the doorway is 1150mm. We don't have a specific stool or vanity selected yet. Re why we wanted to include a seat of some sort - I use the edge of the bath every day, both for putting a foot up while drying off or applying moisturiser etc, and for sitting on for foot care / clipping nails etc. I have to admit that I hadn't considered just using the toilet seat as I'm used to those older, slightly domed lids that 'buckle' if you sit on the centre of them. But I can see now that newer toilets appear to have flatter and more solid lids, so perhaps that is an option afterall. We also wanted to select a stool that could go in the shower - my husband is quite sporty and would love a sit-down massage shower on occasion. I'm thinking now that we perhaps just have a 'wet' stool live in the shower recess (bottom right corner of the plan should be out of the way) and then the toilet lid for 'dry' use. The last picture shared by dreamer is a very nice solution, though if we extend the vanity all the way to the left hand wall we'll have to look at narrower towel racks. Hmm, all very interesting! I'll experiment some more and probably come back to bounce some more ideas off you all. Thanks. :)

if you want the door to be completely hidden within the cavity and not visible when the door is open consider a wide timber architrave around the whole doorway (wide enough to overlap the gap in the cavity) and have the section covering the narrow gap hinged to swing out to lay flat against the plasterboard ...the tall narrow "door" should not need a handle but the cavity slider will need a recessed handle to be able to sit flush behind the cover door ...your secret door should be an interesting project for your carpenter and something like this??