I love rollerblinds for their neat, sophisticated look. Venetians are a nightmare to clean... x) Plantation shutters are worth the investment. Low maintenance and good in wet areas where fabrics/wood may not be so good. I have a mix of plantation shutters and rollerblinds, with a few curtains. :)

I too have a number of windows facing west, in Summer they are covered inside and out all the time. My fav are woven or bamboo blinds, they give good sun protection but still let air through. The all natural ones are recycled as weedmats in the garden beds when they get ratty.

Claudia, do you plan to hang the Roman blinds well above the window frame and divided into two sections for ease of sliding open the door?

As the windows are framed individually I would also suggest two separate roman blinds. Set up to the height of the picture rail will accentuate the ceiling height and tie in with the architecture of the room. To have the blinds at this height will also allow you to see through 100% of the window area when the blinds are open. Where these blinds hang to will also be important to consider. I would suggest the base of the two romans be set to the top of the sill, as to set them lower will show the sill extensions on the left and right sides sticking out. All the best!