I think you have a few options. 1)You could have these curtains remade into Roman Blinds. 2) You could have matching/coordinating Roman Blinds made for the recess and then have the existing curtains remade as dress curtains. You would have to get each curtain split down the middle and re-stitched. For an idea of cost I know our local dry cleaner does this for £10 per linear metre. This would obviously halve the bulk of each curtain. 3) You could buy another pair of curtains, but you then have to face the possibility that the curtain colour won't actually match exactly because of different fabric batches. Also you say that there may not be enough room for all that fabric at the sides.

I found the Dulux Visualator, or whatever it’s called, to be pretty useless. I used it once to visualise my old sitting room colour just to see how accurate it was. My walls were Dulux Elderflower so compared it on the Dulux online thingy and it was completely different!

Thank you plusmarcus. So my thought about the side panels was how do you decide where the bedsides go? Do they sit in the middle of the side panels or do they sit so that the two beads line up with the middle of the bedsides? If you put the bedside in the middle of the side panel they are too far from the bed. And if you put them so the beads are in the middle of bedside they are too close? With the original "B" photo I wondered how the proportions would work with bedsides. Would bigger bedsides in the same style as the bed work better? Sorry might just be my OCD, but where you have them now, for me, throws off the original proportions.

In my opinion you can’t create more rooms than you have windows. So you should give the larger master bedroom to the children and divide it with furniture or screens that can easily be removed by the next people. You would then take the bedroom with the balcony or you would use this space as a living room, make an aperture to the kitchen then add a partition wall to the living end of the kitchen to annex a new bedroom. Be aware that any bedroom off a kitchen may require fire regulation approval.