Ask H&H: bee infestation

Q: Have any other readers experienced an invasion of bees/wasps in an arena? This year, our arena has been invaded by approximately 2,000 of them. These insects burrow down into the sand and lay their eggs. The problem has been compounded by a second invasion of predator wasps that have killed many of the bees, eaten their larvae and taken over their nests. Despite frequent harrowing, we’ve not been able to get rid of the mounds, making use of the arena impossible. I have been unable to find a pest controller who can help. Any advice would be most welcome, as our horses are seriously underexercised due to the hard ground.

LH, West Sussex