Dyson DC07 - how to replace the clutch mechanism?

Hi - DC07 animal - makes terrible noise when in vac mode when rollers stop for no reason - when up right its fine - so believe the clutch is the issue - also there is a loose sort of sound when manually roll the roller - this is currently an intermitant issue.

So now I need to know how to do this proceedure as I cant figure out how to get there - any help very very gratefully recieved

Thanks in advance for all your help and advise

Graham