"when all you need to do is take the brush compartment a
Try doing it and you'll find out why... :S
Going from memory (getting round the visits to the first aid box), you have to detatch the belt from the motor which goes to the clutch, which you can't do unless you have a specific dyson tool to do so, otherwise you have to disassemble the entire nozzle just to get that undone, and then wait for the whole assembly to suddenly snap upwards towards the motor unit with your fingers trapped inside the belt track (cue stream of expletives), then getting the clutch out and disassembled, you need a degree in microsurgery, and something to catch the ball bearings that are inside the clutch that make it do that grinding noise when you jam it up, and then reassembling it with a new set of belts only to find the circlip snaps on you and you have to source a replacement, and when you do you have to go through the process of expletives and finger trapping all over again to reassemble, yeah, there's a good reason I said run away.... :\
Even cheap store-brand vacs are easier to replace the belts on, if you can source them that is...
I don't know if they do it there, but Dyson over here in the UK offer a rebuild program, where you pay a one off cost, they take it back, strip it down (letting them have all the expletive fun), replace broken, defective or worn parts, reassemble and sent it back to you like new, so, you could do that, but you'd have to look up what that one off cost is...