Mate this is exactly the kind of thing I've been hoping someone would actually capture properly. The 3am timing is significant and I don't think that's coincidental - I've read a fair bit about that hour and there's definitely something to the pattern of reported activity clustering around it.
Can you tell us more about the house? Age of the building, any history you know of? And does the knocking follow any kind of rhythm or is it random? That distinction matters quite a bit I think.
I've done a fair few overnight investigations in Hampshire and the wall knocking phenomenon is one of the harder things to debunk because people always want to jump straight to pipes or animals. Sometimes it is, obviously. But when it locks in to a specific time every single night that explanation starts to feel a bit thin doesn't it.
Watching the video now. What camera did you use?