Hello, also consider which way your extension faces...e.g. north or south facing etc, if north facing, I think 2 big square windows ( perhaps SK08 or UK08 size as you have a wide house ) will let in more light. If you have 2 huge ones for south facing and also sliding doors, it could get very hot in the summer. I'm in the middle of my extension 3m x 5m , north facing garden, I have 3 velux MK08 which is 78cmx140cm, I've always liked the look of 3 windows instead of 2 but after they were installed I had second thoughts about whether I should have gone for 2 huge square ones instead as I also didn't take into account that we've have just had a dormer loft conversion completed, it takes a little longer for the light to come over to the back of the garden. Looking at your plan, you could have 3xPK08 94cmx140cm. The edge of the middle velux will be in line with where your sliding doors starts so that could look nice. Or if you have 2, you could have the edge of the second velux starting where the sliding door starts? I wouldn't go shorter than 140cm in length because when you are standing far inside, you want to see more window, if you go shorter, the windows will be 'hidden' behind the steel beams, make sure your builder install them so that the bottom of the velux is closer to the sliding doors rather than closer to the pitch roof. Do you want at least one window that opens with a remote control? Here are my windows, it might help you to visualise..MK08

I'd get as much storage as possible out of it. I do say keep all the plumbed items as close as possible to each other. You have room for more storage. So i'd go with the washing machine under the unit with a corner cupboard for storage. Then the sink unit with another floor to ceiling cupboard for brooms etc. Shelves in the middle. So either this:- The cupboard marked Slimline is so that you have room for all the pipes to be accessed on your Megaflo, if you put a larger cupboard in you'll close the gap, so I marked it as a cupboard, but you may have room for the Fridge Freezer there instead. You have to allow 650mm on cupboards for the plumbing behind and to adjust for walls that aren't true. So if you went with 650 Unit on the left ( above pic ), then 850mm for your door and another 650 to allow for the Fridge Freezer you've used 2150mm , 5mm ( not a lot ) than you already have, so i would be wary of trying to make the room smaller. Obviously the 650mm is an allowance and you would fit those items in, but it does soon get used up.

Ah, looks like your first picture is missing.

I must admit I‘m not keen on rugs right against fireplaces or tv units either! can the sofa in the foreground go opposite the one under the art as just wondering if it would look better? Might be good to see more angles of the room. I only ask to work out the size but I suspect a standard size won’t work. There are a few irregular ones around though or you can layer them or (strike me down) anchor a table with a break the “rule” rug! lovely room 😊