For those who have reached desperation stakes, don't give up yet. Our small plot of 1100 Sq.M was a mess when we moved in at August. I tried teaching them to swim, attempted to trap them with the traditional piège. Stamping around a lot seemed to help, and hammering 3 stakes in to support 3 new fruit trees drove them from the bottom of the garden to the end nearer the house.
In the end we purchased two battery operated spikes from one of the tools trucks, and placed them in the two furthest taupinières. During the very cold snap there was no obvious activity anyway. But in the last few days, it has been quite warm, and only two new hills formed. One was a passage cleaner, but the other smaller one looks as if it was an escape hatch. In the last 10 days we have seen NO mole hills.
Is this the end? Watch this space and take heart!