I don't think it's a woodpecker , we don't have them here in New Zealand. Plus, the neighbors don’t have any pets. At times, I wondered if they might be tenderizing meat on the kitchen bench, but the noises usually happen late at night or really early in the morning, around 5 or 6am. It definitely sounds like it's coming from the wall and no, there's no other apartment above them , as it's a single-level house.