I assume you're not keen on adding a bathroom? Jonathan made a good point re fire escape. Unless you want to use the study as a bedroom, I would think about blocking off the attic access in room 3, but leaving a door through the wardrobe in case ever needed, to create floor to ceiling wardrobes similar to the pic from home design (use of space not style) I'd create 2 rooms from 3 (obviously in the middle of the Velux) for the bedroom and playroom. Build a cabin bed as ASV suggested underneath the 5th and 6th velux similar to pic from ongamagazine. Make the bed 4ft wide for when your son grows. I'd have a built in desk built across the back wall of the study with a shelf above to house a tv. you can use off the shelf pieces but I think bespoke units are key to maximise the space. Pic 3 from earndig just shows storage for a playroom.

It looks great, I'm glad you and your daughter are so pleased and she has lots of room for friends over, playing etc. It can also be easily and cheaply adapted as she grows if she wants. My only criticism (if you can call it that) is that if not already your daughter may soon also want the desk to double up as a dressing table and therefore I think a mirror was a good idea but the memo board (which looks great) can always be moved as and when needed. (I thought i'd posted a comment on that previously but obviously not!). I might also add a desk light there for working during winter months. So which room next?!

Hi. I don't know what colour the wardrobes and bed are but I would decorate in shades of pale taupe or greige with blush pink with white. You can also get canopies for beds which look equally good in adult bedrooms. For wall art maybe ballerina or ballet pumps? There are lots of grown up versions around that should also appeal to your daughter. A chandelier style light and love the fairy light idea perhaps around the dressing table? If there's room perhaps also a small rug that you can remove for when guests stay so your daughter can have her bedding, cushions, soft toys and rug to make it more child like.

what a beautiful transformation. I love your choice of colours as well as the wallpaper, especially incorporating it into the built in cupboards. glad to see you reinstated the picture rail and paid attention to the details i.e bakerlite light switch. just shows how beautiful 1930s houses can be!