My mum lives in a large old stone built house that was once 3 1up 1 down terraced in deepcar on like an old farm court yard kinda thing with the house been on a steep slope up car rd its got a really odd garage under it with a dated stone slab floor its split in to 3 rooms the maine garage then a lil scrap room and a room that had a big heavy locked door that we had to break down it had a big stone slab on legs with hooks above it on the low cealing (probably an old fashioned slaughter room as it was on a farm) but at night we hear banging and sounds of discomfort from down.My mum also insists that when she doesnt shut her bedroom door faces float into the room.
Have you tried to get a copy of the deeds to your house? If not you should be able to get a copy from the holder. It's amazing how much info is on some of the deeds such as plan details, renovations, names of previous owners with their addresses. It's worth a try.