The only product we find that kills them quickly is Neosorexa.
They are becoming immune to lots of others. Pour a few scoops down the holes, cover with piece of slate, and renew as soon as it's gone.
In our opinion, as ex farmers, these have to be got rid of, no time for guilt or humanity.
For every one that you see, there will be dozens more underground, they breed very quickly and in a few months there will be hundreds. These are not fluffy little creatures, they are vermin that spread disease.