In message , Jeff Layman
writes

I can't see you getting lots of little horse chestnut trees. Are you
sure the roots coming up are from horse chestnut trees?

Excellent, thank you. A wall separates the two gardens and the trees
grow in a line along the neighbours side of the wall, a maximum of three
feet from the wall. The roots are the bane of my life, including a
permanently wobbly patio and lining of drains blocked by roots. The
trees are protected.
--
Graeme