A few things to consider indeed, but what a great space to work with... my humble opinion on some of your points and queries... 3) if you haven't already got the cabinet/shelves unit yet see if you can get one with sliding cabinet doors 4) great idea, so avoid any heavy items of furniture (e.g. big armchair) in the centre of the room that will be harder to move/relocate and think more ottomans, bean bags, etc You are absolutely spot on with placing the wall units on the 4m wall and keeping the slightly wider 4.2m wall for seating facing the outdoors a) clearance depends on how much and what kind of traffic going through, e.g. doorways approx 700-800, passage 1000-1200, but to get around a coffee table to access couch or get around behind a chair at least 500-600 and more if you can accommodate... and of course depends on the type of furniture, e.g. if you have cabinet doors that swing open (as opposed to sliding) then you have to allow enough clearance to open the door and access the cabinet comfortably b) I think you can do better than a 2-seater in such a big space... e.g. let's say wall units base cabinets are 600 deep even with swing open doors of 400 you'll need clearance of say 1000-1200 from that wall on the right, which out of the 4.2m wall at the bottom leaves you with 3m... so I would fill up the bottom left corner by having a 3-seater/chaise modular along the remaining 3m with the 'return' chaise on the left along the 1.7m wall c) yes, you'll definitely need one large 'area' rug to define the space... you could even use two different rugs and create two zones... one large rectangular one framed by the couch and wall units and a second smaller round or asymmetrical one closer to the sliding doors paired up with a bean bag or big floor cushions d) I think a tall indoor palm/fern in a nice large pot just in the corner of the units and wall (to your left as you enter the space) would be a welcoming touch and tie in with the outdoors Good luck ;)

Two years later... We ended up purchasing a 3-seater for wall opposite fireplace, a 2-seater for under the highlight window (leaves a comfortable space to enter the room) and an armchair placed diagonally opposite the couches. I've fooled the advice to pull the furniture in off the walls a little. We have just updated the fireplace with the (professional) installation of an insert wood heater and (DIY) replacement of hearth and tiles/timber mantel to conceal the brick while meeting the safety specifications of the heater (required a much wider/deeper hearth than the existing brick one so we removed and replaced with a slab of honed granite, and the minimum height for breastplate/mantel shelf posed a few design limitations). TV mounted above fireplace to allow for better furniture placement. Not quite the picture I had settled on 2 years ago, but works with the style of updates we have made elsewhere. Thank you for all the advice. before: After:

There are existing recessed motorised roller blinds (pale grey). The room is used as a kid's play space by day and an adult living room by night. Toys are stored in bedrooms at the end of the day and the dolls house is not a permanent fixture!

To be blunt -- the room isn't really big enough ! So you have to sort out priorities , and space . You have a dining table , and a computer desk . Can you get rid of the computer desk , by having your computer tower mounted behind the couch or similar , and a wireless keyboard and mouse that you can use on the dining table ? Mount the monitor on a wall , or if you don't need in depth graphics , I understand you can use your TV ( I've heard something about the 'refresh rate' is less on a TV ? ) . Maybe even have a monitor but also the option of using your TV ? Could you use a 'breakfast bar' , probably where the computer desk is now , I know its not sociable all staring at a wall , but it would/could serve as a brakfast bar and computer workstation . Could you get rid of the dining table and chairs , and have a large coffee table , or 2 smaller ones , and eat 'casually' ( my polite way of saying eat sitting on the couch ) ? Even mounting the TV on the wall will let you get rid of the cabinet , but I gather you have gaming consoles in there ? And the present arrangement with the pot plants uses some space -- maybe some shelves with them on will still retain the plants but free up floor space ? Just some thoughts off the top of my head .