Great room. The paintwork, bulkhead and black aluminum window look contemporary, so updating the colour scheme will completely renew this bathroom. I would remove the tiles on the wall of the vanity, including the bath area, and actually have a glazier I stall a mirror from the bench top right across the room, thus negating the need for tiling at all, and just lengthening the space and light. Then all you need to worry about are the bath surround tiles. Luckily there are loads of options, from DIY to designer and many in between. I saw a tile product on houzz called xlight that can be applied right over existing tiles, as long as they are level and secure. There is a stunning architectural range including concrete looking tiles and even a marble. Carrara is the most expensive fit out choice but number one of designers, xlite have a tile which would tile tour bath front in one piece as would your side and rear wall, in around two sheets! Contact them, then all you need to do is replace a vanity, or I would have a joiner come out to quote on hand laminating the top onsite. Or consider just replacing or building a base draw vanity beneath this while retaining the bench top, you could tile this also in the marble look for ultimate luxury, and go with a timber veneer looking product for the suspended drawers below. Floor tiling is the only thing to do then.

A quick fix would be to paint the tiles. I've never used tile paint and have read a lot of mixed reviews, some people swear by it, others suggest it's of no use. My understanding is it works well if prepped and applied properly but will eventually show wear. You could paint the tiles the same white as the walls for a complete shabby chic freshen up or go with a feature colour like teal (or any colour that takes your fancy).

based on the accurate dimensions the most economical update would be to replace the spa with a shower over bath, keep the existing vanity and toilet, reuse existing taps and retile but, any bath renovation is always much more expensive than imagined, and the unexpected expenses (eg asbestos under tiles) can add up and a minimum of ten thousand for a very modest upgrade wouldn't be surprising...If the bathroom is in acceptable condition especially if there's any possibility of a future expansion towards the backyard that could affect the current position of bathroom and laundry) i suggest (subject to confirmation from a plumber) that you consider reorganising the other spaces and sacrifice the wiw to create an ensuite with linen storage taken off the middle bedroom..surprisingly an extra bathroom could be less expensive than renovating the old one but i would still allow at least $10,000 with careful planning

For storage, I used a mirrored lift up cupboard door above the sink area in my very small ensuite with some success. We put power points inside the cupboard too - it was a very good place to have them as the door lifts up & is out of the way. I also used some of the wall space to allow slightly deeper shelves, without the cupboard jutting so far into the room. The cistern was recessed into the wall cavity, (in our case below the window) & it worked well to save a little space in the room. Photos are not very good, but I hope you can get the idea.. It worked very well. The ensuite was 1mx2m. We use vertical towel rails. They're really good & very compact, but do make sure the electrician installs them up the right way. They work on the heat rising principal & do not work well upside down as ours were installed!Hope this is helpful. Good luck.