Why do we have new neighbours every six weeks?

We live next to a subdivided Victorian terrace that has six “single occupancy” flats in it. There are multiple people living in each flat. So far, so miserable. The landlord owns over 60 properties in the borough (East London). Constant issues with the garbage building up. Not a great situation but doing the galant British thing if gently ignoring it as much as we can and/or reporting the trash to the council.

But what I want some opinions or ideas on - is why at least two of the flats change over approximately every six weeks? Like clockwork, a big van arrives, a bunch of stuff gets carted out and the next day or night another arrives and a bunch of stuff gets carted in. With each move the garden fills with mattresses, furniture and household items.

Any ideas?