The radio and the clock have just gone blank in my 2008 swift.

There's no way to easily check what's causing your power problem. You may have a short in your 'hot wire' or the red wire coming out of your radio (I'm assuming the ground wire hasn't come loose and shorted out the radio, but that is something to consider also....as long as you don't smell something burning you should be ok). The problem with newer vehicles is that the radios have been made 'theft proof' by forcing you to remove pretty much the entire dash to get at them. Unless you or someone you know is mechanically inclined, I'd suggest taking it to a garage...sorry.... :(