How can I configure OS X Mavericks to use a UK PC keyboard layout? I'm using a non-mac USB UK keyboard with Mavericks.  Because Apple's idea of a UK keyboard is different to a non-apple UK keyboard, some symbols are wrong, e.g. " and @ are swapped.

How can I get set my keyboard layout to match a non-mac UK keyboard?
If the British PC layout from apple is not right, some alternatives can be found at

http://liyang.hu/osx-british.xhtml