After receiving NO help from pc world (the guy patronized me in to a frustrated rage so I left) and no help from Apple I managed to 'solve' it by uninstalling Spotify.
Not ideal, but at least there's the web player.
Adobe CC doesn't seem to make any difference to me, which is what someone else suggested.
Since uninstalling Spotify I've (touch wood) not had it again.
It's interesting (I've not been back to this thread for a while) that there are a number of people that are experiencing this, and yet there's no 'official' recognition. It's not solved, as far as I'm concerned, because it means I can't use this computer for what it's designed. But true to form it's probably a 'but you're using it wrong' response as per usual.