You're lucky to have those tracks, they would of been custom made. Depends on your budget really. If not much- cut down what you have and hem them. If more $$- I'd speak to a curtain maker. Remove the pelmet and have a 2nd track attached to the one you have for a sheer curtain (to hide/soften your bars but keep the view and light). I'd then use the existing track to get some nice block-out curtains made to close of a night. With well made pinch-pleat curtains you won't need the pelmet.

My advice would be to get rid of the blind as you won't use it once you have the curtains - perhaps you could use it elsewhere or have it as a spare. You would probably find that without the blind you will use the access more often. I would do full height and full width drapes - an inverted pleat is attractive with heavier fabrics but if you have the light fabric on the top keep it simple. How about putting your sheer lighter drape on the side closest to the bedroom and have the blackout lining behind. This gives softer look in your room. You would probably find that without the blind you will use the access more often. If there is a lot of sun take care with the pure linen cotton and natural fibres as they will rot with light and sun. There are many synthetic linen look alternatives that are less expensive, last longer and have the same look. I feel your room could do with some texture - you could possibly have a subtle self coloured stripe in the drape - or go plain and have the interest in your bedding. If you want to go soft grey drapes I would go for a darker charcocal or midnight blue/ teal colour on your walls which would look awesome with a soft grey linen look curtain and natural bedding. You could introduce soft mustard, peachy pinks and soft apple green linens in your bed cushions.

Hi You can also get a gyprocker to make this up as a premade L shaped bulkhead then it can just be attached with some angle on site. We do it all the time for coffer ceilings. Try talking to your local ceiling installer. Cheers

another idea if you had a plain pelmet that was within the alcove that came from the bottom of the picture rail to the top of the window and flush with the walls on both sides painted the same as the wall colour., you could then run your black curtain rod across the alcove pelmet which would look like the wall. When I had my Ferderation House we painted the bedroom walls up to and including the picture rail in the same colour. The wall above the picture rail and the ceiling were painted flat white, along with skirting boards, an old painter told me about this and it looks brilliant. A couple more photo's for you with different looks This is similar to what I have tried to explain by running a plain pelmet across the whole alcove and then the black rod running from either side outside the alcove with the curtains against the outer wall, the pelmet would look like part of the wall.