Hahaha, I can't imagine a PRO would give you a hard time in this forum! It sure sounds like you've got your hands full. Gosh. I'm in the states. East Coast. In my experience for this area I've worked with a designer most recently who charged $150 per hour. We spent about 6 hours over a 2 day period where she advised & kept me out of trouble getting a color palette together. We went shopping and she helped me chose bathroom tile and plumbing fixtures, kitchen appliances. She's very efficient and we accomplished everything I needed. She billed me $500 at the end of the month and I pd her like that. I know it can get more expensive and complicated when you want them to choose fabrics, furniture etc.

expect $20,000 plus appliances and tradesmen another $10,000 but is this for your home or for the rental

it could actually be cheaper than changing the upstairs kitchen but only the trades would be able to confirm a realistic price for demolition and installation of new plumbing... your proposed floorplan looks good except the master bedroom won't fit the wiw as drawn, the upstairs lounge would be better with access back and front to the balconies with bed 3 and 4 at the side and what about the new kitchen in the downstairs storage area which doesn't reduce the size of the new living dining room and retains the big garage and ...why not ask a few real estate agents for a selling price as is and with the proposed upstairs or downstairs renovations...

Wilson, one way to accrue a list of potential builders, is to drive around your area of Sydney and make note of which builders and building projects similar to yours as well as those who are currently building houses you admire. I would compile as many as possible and be discerning in your list. You might also notice how long particular builds are taking and if tradesmen are regularly on-site. I realise in Sydney this could be a big job, but it may well be worth your time. Then, check out the builders' websites to see their projects and any reviews. As you move closer to short-listing builders, make an appointment to meet with them to show and talk about your project. You will get a better feel for who you think you can work with, any creative ideas they may have to improve elements of your plan, reduce building costs, etc.