Tricky - with the machine standing upside-down you need to insert a medium flat bladed screwdriver between the clutch knob and the clutch at the 6 oclock position and gently pull the knob (if you pardon the expression)! Hold the er knob then do the same at the 12 oclock position. Hopefully you can remove the knob then the clutch. I don't know why you guys struggle - Dyson have the best repair service - give them a call and they'll sort it.
Adge, June 2007