Technology still seems to have long way to go with regard to the design of central heating radiators. Even relatively modern versions are rarely elegant and their associated pipe work does little to enhance the overall appearance.
The answer of course is too hide the offending radiator, but suitable ready-made covers seem to be both very expensive and rather flimsy even if you can find one that is the right size.
I was recently approached to make a custom-built cover for a spare bedroom radiator to match the existing painted decor, and having made several in the past I know that it is a relatively simple construction job. For anything painted like this, MDF is the ideal material despite the dust drawbacks and the problems with finishing.