"bumping" this thread rather than start a new one..I had exactly the same issue as the OP (Mowerman). I followed the Mvacs link and found the very helpful guide..and guess what I have the self-same cracked fan..5 years light use but hey-ho.
Hence the question do Dyson sell them? (don't laugh!)..OR
Does anyone sell them?..OR
How best to get hold of one?
any suggestions gratefully received..seems a shame to have buy a new turbine head for the want of cheap fan..but I guess that's the way the world is these days..nevertheless hoping someoone can point me in the right direction (& will keep trawling the net..if I find one I'll post source)