Yeah Ooh, that is gorgeous fabric! Are you thinking of using that for the curtains? If yes you'll want to use that where the curtains are drawn to show it to its full glory. Wow, that's beautiful! And Carolins is right about the fretwork against an aubergine accent wall, in the right cream that would be stunning.

Would you consider Plantation Shutters? They can be made to measure, are great for privacy and great to keep Heat from escaping! People commonly think they can darken a room, however if you opt for white, they are highly reflective when they are open- and stream light across the room. californiashutters.co.uk are very reasonable and show you how to measure and fit yourself. We fitted these in our own home, and are thrilled to bits with them! Good luck!

I'd put the day bed in the opposite corner behind the door going lengthwise to the window. The day bed will be too high for the low window and may look odd. Plus, i think the change will allow for better wardrobe and drawer space. As it is going to double up as a guest bedroom, do you really want all of your stuff on show with open shelving? I'd maybe try the Ikea Pax system, easy to buy what you want and fairly easy to construct, but i would have doors. You have to decide between walk in wardrobe or bedroom with wardrobes. Alternatively, maybe consider a high bed with wardrobes and storage underneath with extra on the other walls. By having something purpose built it will allow for more versatility and more floor space. They certainly don't have to be childlike these days. I'd post dimensions if i were you,

What a fabulous feature! Rather than hide it with curtains, why not use a fine translucent material that allows a more subtle visibility, couple with a few plants and some low mood lighting to turn it into a little eco-world?