I don't think I could cope with an open plan bathroom, I like wet areas to be totally separate, the steam entering the bedroom would be of concern and I would not want to even think about a toilet. We did not even like the idea of having the ensuite opening directly off the bedroom, instead have the dressing room opening off it with the ensuite opening off that. Having the dressing room between the ensuite and bedroom totally minimises noise. I find it far more convenient to walk from the shower directly to the dressing room to dress without even going into the bedroom.

I would leave the render colour and just tile a trim around the base in a pattern and over the arch of the brick. But I also recalled the pizza oven at a pizza place where I grew up. They make great pizza, but the oven is so cool! You could do something like this!

Thanks everyone who offered advice. I've attached 2 pics of the almost finished project. Can't show the bed as the picture isn't up yet - my partner went to clean some mildew off the ceiling, didn't secure the A frame ladder and only wearing thongs almost severed his big toe when it collapsed underneath him. So a warning to all! Please don't get up ladders that have not been locked or wear unsafe footwear. The mirror and rug were from Gumtree and I made the curtains myself (thank you Spotlight for a sale on curtain fabric). We're very happy with the results (apart from the hospital visit involved). Statement light fitting also needed at some point.

answering your questions: change the sliding door to a bench height sliding window and use the salvaged sliding door in the western end of the dining room where the best entry position is for the deck, you MUST have a proper legal drains do not consider anything else...the drain pipe for the garage laundry can be on top of the concrete floor, behind the washing machine and through the sink cabinet and/or under built in storage and only needs a few cms not a whole floor and no stepped up area that you would see or trip over.. the laundry can't be in a separate room as there's not enough space for a separate laundry without compromising the size of the garage...a laundry cupboard 80 cm deep is enough for the washing machine (allowing for the drainage pipe) you could use the old line cupboard to store anything you want but it's not cost effective to change, the entry foyer is already as big as in many modern homes and there's generous flatpac biw space in the small study.... the family bathroom is 2380 x 2370 (ie the old study minus 1m for hall way and wall thickness and, arranged exactly as shown to allow for the wide window there should be space for a bath up to 1800 x 750, vanity about 1200 x 500 and shower space 1200 x 800 and leftover space makes the small linen cupboard with the door deliberately opening towards the shower to use the back of the door for hanging racks for towels and clothes....btw i understood your priority was maximizing separate sleeping rooms and minimising costs...my last plan has five separate sleeping rooms plus the lounge with sofa bed totalling sleeping places for at least 10 people plus the potential for bunks in the garage so you need to decide what is most important and where you're prepared to compromise