Good point. I hadn't considered that. But no, no potted plants (or similar, and I would keep the pot plants...) were moved.
Not AFAIK - the house was fairly modern and no spirit manifestations or portals to the netherworlds were apparent.
Well I guess it might have, but seeing as I walked along that path daily, back and forward, over the course of many months and hadn't spotted it until then, it seems extremely unlikely.
That part of Hemel Hempstead was rather posh and well kept, with no litter, and the paths kept clear and clean, doncha know.