FWIW these seem to be the right size replacement rubber feet
22mm x 11mm Conical Recessed Rubber Feet
http://www.ebay.co.uk/itm/360718567706?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
Mine were perished and falling apart..
and it took two goes to get the right size
obviously the feeder heights will need to be reset after fitting.