Does a new clutch have to be 'run in' ?

not really,but dont ride it and dont leave your foot on the pedal,they can glaze up and leave hot spots on the flywheel-----cracking eventually.small hair lines later on,you will see later on when its worn out.

YES THEY DO NEED TO BE RUN IN!!!!!!!!!!! But normal driving is the runin process. Drive 300 - 500km NORMALY. No skids, riding the clutch etc just normal driving. Like hans hartman said above the fly wheel can glaze and get hot spots if you don't and the problem will just keep getting worse and worse!!