aeg03 (can't see the link!)
I did have a DC04 for a short time; swapped it for a friend's DC07 'All floors'.
I don't remember the DC04 (purple & pink model) having particular problems, but the DC07 did. I ended up removing the exhaust filter lid, ripped out the standard filter, cut up a DC02 filter, and trapped that under the lid. It also had the benefit of sealing the gap at the back of the filter lid, where the black dust came out.
The DC11 was another useless piece of shit. The hepa filter would not stay locked in place, so much so that when you used the machine, the heat deformed the parts where the filter was supposed to lock into. I ended up linking two long cable-ties together, looped through the locking holes, straddling the filter, connected the ends together, and forcibly held the filter in the position it was supposed to be.
Having owned, and used, various Dysons and seen friends' and relative's models (DC01s, DC03, DC04, DC05, DC07, DC11, DC14, DC15); I think they are quite flimsy machines, poorly designed, cheaply made and certainly not worth the asking prices. Yes, they are the best bagless, but others are catching up, and you still cannae beat a decent bagged cleaner. (Try sucking up large quantities of powder or soot and the Dysons haven't a hope in hell).