We have had two Kedron Vans both have had two Sirocco fans fitted. I think they are fantastic until they need cleaning. Not sure of what happened to the directions on how to clean them.
With the help of Google "Cleaning Sirocco Fans" I found a couple You Tube videos. Suddenly the task of cleaning the fans became a pleasure. If you hate cleaning the fans, do yourself a favour and do what I did and watch the demo. I will no longer have to look at a dirty fan.