All I can think of at the moment is beautiful large canvas art work, dont know what your decor is but I am sure you could find some thing to suit.Or maybe have a board you can hang over the box fits the width of the wall and the length in line with the top of the bar on the glass window on the right, then make a phot collage! Once you have the board or canvas to hang you can use any art form you like!

another idea is to hang a panel curtain in a printed linen fabric [pattern? ] over the top, easy to do and inexpensive.

I believe a laser cut wood panel which is hinged onto some type of timber frame so you can access both the radiator and electrics. If they are all painted the same colour it would make a nice feature. Just a thought.
http://houzz.com/photos/1524295

Thank you all...ove the laser cut wood panel idea and the curtain panel idea also.Here are a few more photos rawketgrl.Hallway is tiny so I think I need to utilise the area for shelf/storage/mirror/lamp area etc rather than purey decorative.I saw this black glass radiator cover for sale ...place a black shelf above it...would black be too dark in this area?

What about adding something like this photo to conceal the area...with cabinet doors rather than open shelf? and radiator cover and shelf below?

Would you have enough room for something like this? Then perhaps you could install some narrow shelves above and decorate to obscure the electrical box.

Sorry, hears the photo
http://houzz.com/photos/2606364

Hears?? Make that here's :-)