Probably just do a Google search and see if there are any photos of the part which would give you a clue.
Oooh look: Within 30 seconds I found this:
http://www.yourspares.co.uk/parts/kenwood/breadmakers/bm200/parts/ys658709/kenwood-bm200-drive-dog-KEN661531.aspx
Looks like it is held on by a clip.
Make sure you note where the washer goes
Anon, September 2016
