Just be aware of shredding posionous shrubs and plants in the shredder such as laurel , ivy , privet , laburnum ( any evergreen ) . Best to rinse the shredder out with a few kettles of fairly hot water before plugging it in and give it a couple of cold rinses .
Would shredded cabbage be any good ..buy dutch cow cabbages etc from a wholesale veg unit or ask them for some of their green waste . close to us we hsave a veg prep unit that preps for hospitals , schools and nursing homes etc. they sell their waste for compost usually but do on occasion seem to sent people away with small domestic trailers of green waste.
Perhaps even a hotel or two could help with green waste as I think their cooked food should be seperate from compostable stuff.