It looks like the little kitchen area has now gone so I would create a booth style seating area in that space. The piano I would then put at an angle in the other nook facing into the room as a feature corner. The rest of the seating would then be in the main central area. I think ultimately this depends on the budget you now have to finish the room, whether lighting can be changed to incorporate some features and task lighting/pendants. Have you considered having a designer look at the space? I work remotely and include lighting, layout and accessorising in my PDF remote designs. As you already have the wall colour and flooring sorted this you would be surprised how affordable the price is :) best of luck. It's looking great so far.

I would put the washer and dryer in the middle of the opening so that they are easy to access and then use the sides for stuff not used as often such as ladders, DIY equipment and tall stuff like the ironing board and vacuum cleaner

I couldn't work out how to add photos to my post (first time here!) so started a new post instead, with plans :)

thanks everyone for the suggestions. unfortunately the width on these rooms has now gone down to 1.8m instead of the 2.1m shown on the drawings so having a corridor in that space would leave us less than 1m to play with for 1 of those rooms. looking to utilise space from the toy/home office below. any suggestions welcome thanks