Cost of new electrical pit

I am looking for advice about who should wear the cost of a new electricity pit. I bought a house, planning to demolish. That house was connected to an existing electricity pit. I got my planning permit for the new house and about a year later demolished the old house and from that point there was no electricity supply to the site. In between demolition and me now starting to build my new house my neighbour subdivided their land and two new houses were built. United Energy are now telling me that because of the new houses the existing electricity pit is at capacity and a new one is needed and that this will be my cost (approx $8.5K). This does not seem fair to us given that the capacity of the existing pit was used up through no fault of mine and with no consultation with me, even though I already had planning permission to build my new house. Thoughts?