Had this at my old place in Sleaford for about three weeks back in 2019, dead regular, always between 3 and 4am, three knocks then silence. Turned out to be the pipes expanding as the heating kicked in on a timer... except the heating was set to come on at 6am. Never did fully explain that one to my satisfaction.
Anyone else noticed a pattern with the number of knocks? Three seems to come up a lot in these reports and I dont know if thats just confirmation bias or if theres actually something to it. Would love to hear if anyone has ruled out the boring explanations first before going full Most Haunted about it.