Virgin Media are performing an installation across the road from me, which involves some external work, and this morning I've discovered they've dumped a large blue sack of (I think) cement or similar and a full rubbish bag in my front garden. I'm not a Virgin customer and I've had no contact with the workers, let alone given them permission to dump their trash on my property.
Where can I raise a complaint to Virgin regarding this as I'm not a customer?
The work is undoubtedly being done by sub-contractors, and VM's management of these is notoriously slapdash. I'd suggest you report it to your local council's streetworks team (not the waste disposal team) as fly-tipping of debris from "Section 50" streetworks. There are rules concerning construction waste handling, along with obligations to not create a nuisance.
That is more likely to result in the matter being addressed than complaining to VM.