from your description of 'bolt and flanged bush' I believe that your rear derailer is a 'claw' type mount.
Sometimes, when removing the rear wheel this claw can get slightly moved if it was loose.
so if this noise is a new problem, check that first.
on the other hand; if this problem has been persistent in the past; it may be that you need more b-tension to pull the derailer away from the lowest/largest gear, so it doesnt grind/rub
it also sounds like you have a below-tourney-level RD, in which case there is no b-tension adjustment, and you just have to put up with it, or upgrade.
Found a decent photo online:
http://bicycles.stackexchange.com/qu...-34t-megarange