I serviced my mower this morning and gave it a clean with a hose with a moderate level of water pressure. It appears that I have blown a part off the lawn mower though I am not sure how. I can't figure out where the part came from and am hoping someone can identify it so that I can narrow down where it might have come from.
Image of front and back of the part:
Click image for full size
The inner part spins free of the outer part and that's about all the information that I have.
The mower I have is a Rover i5500 and the manual is rather light on pictures or diagrams so it was not much help, the manual is also quite easy to find online if that is of any particular help.