There probably aren't many more of these around any more, but the procedure may be similar for other models.
The fault was that over time it gradually loses suck. The filters are clean, but it sucks less and gets hot. Today I went to pick up some plaster while /she/ was out and got no response at all - so I took it apart.
This is what I found:
Since it had been a bit of a pain to do I took photos as I put it back together. Disassembly is the reverse of assembly :)
This is what it looked like after cleaning:
Put the conical inner cyclone back into the outer, and line up the flange with the hole
Push hard to put the two bits back together. I found a bit of gentle warmth (hot water) to soften the plastic slightly helped, but it still took a lot of force - there's a ring around the inner cyclone
that makes them stay together. A LOT of force - I put it on the floor and pushed.
The rest of the grey bits go back together easily, but make sure you have the screw holes lined up - the one in the housing , the one in the pressure valve in the top
and the one in the cyclone . Finally slide the entire cyclone back inside the housing, making sure the bump lines up with the divot in the housing .
You can then replace the screw
and then push back the rubber seal that hides it . The yellow clip just clicks back into place - the spring goes on the plus-shaped bit.
When taking it apart the yellow clip needs to be prised out first, not forgetting the spring underneath that will make a bid for freedom. You need a thin bladed screwdriver to open the housing slightly so it comes out. It doesn't look like it wants to, and you really need about 5 hands. This lets you get to the torx screw.
There's only one screw, but the grit and dirt which is why you started means nothing will want to come apart.
Andy