Tír Na HiFi

That wobbly stuff could be anything Simon. Floor laid just a bit too tight to the wall and springing up. That could also be because of moisture either rising damp, leak etc and the floor has spread. Light laminate floor also will have a tendency unless it is weighted down and on a mirror flat floor can rise. More than likely the latter.

If you have any weights from the auld gym days maybe try a few of them in the worst spots or just get a few concrete blocks(not joking).That option is cheap and cheerful and let's you know the score.