i'm told by my sister who spoke to a master composter in shrewsbury(don't ask!!) anyway he recommends that each time you go past your 'darlek' bang on the sides rats no like it !!
I always bang mine......and pause .....before removing the lid.....gives them time to shoot out the bottom....oh stand back a bit too after the banging on the side.
I agree that banging on the bin can make them move on but only works if you're there to do it frequently.
Mine must be full of rats as I haven't been down for a week now thanks to this horrendous cold i have. Can't do anything strenous without a 5 minute coughing fit. Have to take painkillers for the rib pain. :(