Oh look there's one!

Neil the forester came  to inspect the guillotined treelets (here) and to advise on the best way forward. He said if we can locate the stumps and mulch them then they have a good chance of recovery. Much of the day was spent doing this BUT it was a challenging task to find the tiny spikes under the heavy layer of cut grass, docks, thistles and more - real needle in haystack stuff. 
The trees that cannot be found, or fail to survive, he will replace during the winter dormancy period.

Our neighbour has been informed of the probable  cost and the culprit, we assume, remains under a mantle of disgrace.