Blocking a public walkway with personal building materials

The neighbouring house has had a delivery of building materials dumped in the alleyway to the side of our house which now blocks a public walkway for other residents of the Close, there is also more building materials left on the pavement blocking that as well. They are also driving into the alleyway with vehicles and diggers which seems dangerous to people using the alleyway which is for public access. There is a concrete bollard halfway through the alleyway to prevent driving through it but maybe an additional one at the entrance would prevent further abuse in this way. The delivery truck also backed into the alleyway causing damage to the grass verges and our fencing.