If possible, I’d change the blind - a Roman blind with colour / pattern would be great. I’d look at installing a slimline shelf over the radiator which would help take the focus off the radiator. A mirror or artwork opposite the window would be good although you might need a door stopper so that the door doesn’t crash into it when it’s opened. Then I’d have a floor runner / rug by the door.
....or a lovely radiator! ;) There are lots of lovely slimline options these days, which would definitely "uplift" the space. Let me know if you need any advice.
tamp75