Appreciate the help but haven't quite got it to work just yet...
I successfully loaded the base21 skin into the game.
The base21 download didn't contain a 'match' folder so I created it and copied the fixture details.xml into it.
Is this correct?
I'm suspecting not - the game doesn't appear to be reading the fixture details.xml file as I can delete some of the other bits of code (non Odds) with no effect on the Schedule screen in the game.