A version of one of these might work for your dilemma. Surely one of them can be tweaked to work for your window.

I have a weird shaped window that I am having difficulty solving. I need to be able to control the light, while still being able to see out. The room gets cold in winter (south facing), and hot in summer (gets sun early morning and late afternoon). I need to control the light so my fabric and paper don't fade, need the lovely even light for working, and have a lovely view from my desk. Venetians or vertical blinds would be perfect except for the angles. Any suggestions?

It's the window leaf itself that has bowed. Have attached couple of images that hopefully explain it better. It varies with each window but a lot of them have just warped all kinds of ways. The one below is probably a bit hard to see but has bowed in the middle.

Looking at the bench , I assume that aged look is what you are going for ? How artistic are you ? I'm thinking you'd carry on in a similar vein -- paint the trim in white , but while its still damp ( so within say 30 minutes ) dab on some off-white and even buttery cream , using a sponge , in a bit of a 'rub' pattern . Likewise , I quite like the faded blue jeans look on the sill -- thats a bit harder to do , but maybe a cream base , then thin the blue with turps or water , and also sponge it on , but basically in solid rubs , like you were nuggetting your shoes .