I did that just now. One thing I noticed when I was doing my test ride after adjusting the front mech is that the ratcheting noise has nothing to do with the drivetrain (except, possibly, the hub). It actually does happen when I'm freewheeling, and seems to be something rattling, but for some reason it's exacerbated by pedalling. When not pedalling, it's a very subtle noise. I've checked the bolts on the side of the headset already (not the one on top, don't know what it does), and everything seat related is well-greased and tightened up.
Same goes for the bolts on the chainring, crank and pedals.