May I go back to moles, the reason is that I like moles!
The standard treatment I was taught for unwanted mole hills was to stop or reduce watering of the lawn. The reason is that if the soil dries out in many soils this makes it difficult for the moles to dig. They will find somewhere else to find food. You donÃ¢â‚¬â„¢t have to do this permanently, just every time you see mole hills.
It takes about a week or so. You will find that the runs are either abandoned or that there is a line of mole hills heading straight towards you neighbourÃ¢â‚¬â„¢s garden.
The other point to remember here is that much of what we refer to as "mole" damage here in North America is really voles, a far more active and aggressive creature. Reducing grubs will help, but probably not eliminate vole issues. High frequency transducers are initially good, but the creatures tend to develop an apparent immunity...