Alan, Hi there, can`t say I have had the same problems with my Rhino other than the rear slide locks allowing too much movement, and to solve this I just wound some duck tape around the centre of the catches thus restricting any movement.
Okay regarding the fan, as it is mounted on the side of machine (had the same problem as you on last portable - Truvox President).
The only small problems I have had with the Rhino are - solution valve at front was leaking so I replaced with a better double ringed one, had to re-stick foam ring back down onto inside of lid, ball kept coming up in filter (common problem with alot of portables I believe) so I pushed a piece of metal down into between ball and mesh to prevent it coming up (if you do this always remember to empty dirty tank before it fills up) and one of the vac hoses inside of machine was melting a little as it was feeling the heat from one of the vacs, again I just sealed around the hose with some duck tape, checked it again recently and was fine.
Considering the price I paid for my Rhino from Matt from Cleansmart (£1770 inc VAT) All in all this portable has been a good buy for me so far, especially when you look at other similar specification portables for twice this amount of money.
Nigel.