We've tried gas capsules - didn't work,
We've tried traps - gets a few but does n't get rid of them all,
We've tried petrol - good fun but does n't seem to be that effective,
However a two-stroke motorcycle's exhaust connected into the burrows and left running for an hour or two does seem to work!
As for the humane methods - you're wasting your time, they'll be back the next day.......