Can you keep the hall, at least partially, so the bathroom opens into the hall and not into a public room?

Edited to Add (ETA)...upon further study, it appears the hall is still there. You've added another Bathroom, from what I can tell.

That Dining Room looks very small. Add in the four doorways (Bathroom, Bedroom, Hall, Kitchen) and I think you'll find that it's not big enough to be used for a Dining Room.

ETA...It appears to be the same size as it is currently, how do you find it now with all those doorways? Can you fit a decent size table & chairs and still have room to move around when people are seated at the table? I still maintain that you don't want to be looking into the Bathroom from the Dining Room -- especially at the toilet like your layout shows! It really is an "ewww" factor for most people.

It looks like you're doing the following...please correct me if I'm wrong...

• The WC is being combined with the current Laundry Room to make it a larger Laundry Room.
• I think the current Kitchen is being converted into a 2nd Bathroom.
• I'm not sure about the current Bathroom space...is it staying a bathroom so you now have two bathrooms?
• The current Lounge is becoming Bedroom #3
• The current Dining Room, Sunroom, and Covered Porch plus the addition are being combined to make a Kitchen, Dining Room, and Lounge (or, Living Room / Family Room as we call it in the USA).
• The addition is extending the back of the house to where the outside wall of the Covered Porch ends and extending it across all the way to the right. It's also extending the "Sunroom" space to the meet the right exterior wall.

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Like this?

A little more information would be helpful. How much are you extending the sun room? How do you enter the house post renovations? One thing you should do is wall off the door from the dining room to the bedroom. You have access from the hallway.

We enter the house where the arrow is on the original plan. Correct in saying, what we would like to do, is create a new Kitchen dining and lounge area out the back, in other words extend the sun room. Convert the WC and laundry into one to create are larger Laundry storage area. Add an additional bathroom (the existing one to be converted into an En-suite, with new door opening to adjacent room. Also add in a study area. We would like the sunroom extension to include the dine area however we think it might be too tight. The overall new open plan area will be 5.0m x 8.3m clear. One thought was to create another hall way also by creating another opening in the wall between the front entry and dining area. and create a study nook along a new hall way. We would like to keep the existing lounge as second lounge but also have the option to use it as a third bedroom.

If this is the entire house, then I think you're trying to cram too much into a limited amount of space.

Maybe if you reduced the size of the Bedroom/Lounge to no wider than Bedroom #2 you might be able to fit a hallway there. The Dining Room would probably still be a bit tight.

You might try posting on either the Building a Home or Remodeling Forum and ask them for ideas.

Building a Home: https://www.houzz.com/discussions/building-a-home

Remodeling: https://www.houzz.com/discussions/remodeling

Cheaper to sell and move that to plan this money losing addition. Buy someone else’s renovation. https://www.remodeling.hw.net/cost-vs-value/2019/