I'd love to see the glitter wallpaper your girl has chosen! : D (something tells me it is pink...) I would use this in the shelves as it makes her happy, is possibly easier on the eye than a whole wall in the paper and easier to change later on. Romans are probably the best choice for the window dressing.

Yeah Louise I've had a look and they are expensive. I've made my decision now and am going for wide wooden venetians on their own. I've wanted them for quite a while just wasn't sure if they would be ok on their own. After looking at lots of pics I think they will look great. going to a Hillarys store later and they offer a measuring service or I can measure them myself and go via the web-blinds site so much cheaper to do that. Going the whole hog and getting them for the whole house. Really appreciate everyone's time thanks to all of you.

Going with a roman blind would be a good choice, the soft fabric won't look out of place next to the curtain - https://www.makemyblinds.co.uk/roman-blinds/

Full height curtains, on a track that extends past the doorway. When open, full light and visibility. The fabric will add to your room too. Might be pricey, but if you have budget constraints then IKEA curtains have a great drop and you can join a few pairs together if needed. In my lounge, we’ve put curtain tracks behind coving to hide them, like you see in a hotel