No doubt you'll get the blame when it goes wrong anyway.
or the bolts shear and he damages the fence anywayIf you were to go back to the drawing board then spring loaded bollard would be the way to have gone but IMO it they are to protect the fence then they need to be solidly anchored. If lorry got damaged then it'd 100% be drivers fault so he's have to explain to transport manager why it happened. Shear bolts on bollard could be driver gets no damage to vehicle and therefore no indication it was them who damaged fence !
Get rid of the bollards and get the neighbour to stand in front of the fence.
Problem sorted