Coldrum

I'm sure that's true to a certain extent, but treasure-hunters do less damage than labourers paid to destroy. Addington Long Barrow supposedly contained a gold cup, making you wonder if the same story existed for all of them. The chamber was dug into and collapsed due to the lack of stability of the sandy soil but Chestnuts and Lower Kits Coty could well have been ransacked, stripped clean and left almost bare, just standing stones, before being pushed over. I believe myself that Coldrum, being isolated from much human contact, survived any intrusion into the chamber other than what occurred when chalk was being stripped away beneath its outer end [however long that may have been], and even when the capstone was ripped off and the stones buried, the exposed chamber contents were still left alone. The rumour of the tunnel has caused a lot of repeated damage over the years, and the hole has been plugged once already.

I don't notice any evidence of anyone looking for the tunnel at the church end though!