True, especially after they knew about Uncle Jack. But at the beginning it just seemed that someone or some creature was upstairs so surely you would have gone up to investigate? Or why not wait outside as the footsteps started above them so that they can see whoever or whatever it was exiting their window and jumping down onto the road?
Also, to be blunt, if someone is getting into your house and exiting through a certain window then the very first thing you do is to secure that window so it can't happen again, because if they are getting out that way because there is a good chance they are getting in that way, too (perhaps with a stepladder).
Them you have the known fact that the guy worked with computers so if they didn't want to go upstairs then why not set up a camera trap or leave a video camera running? Or at the very least sprinkle some flour on the floor to get the footprints of whoever or whatever it was?
But then I have always thought it a bit odd that his partner Jay was the a direct descendant of Jack and the cottage was still owned by the family and yet she didn't know about his ghost? I'm inclined to believe that they knew it was haunted from the outset but it makes for better drama if they find out from the friendly local. Otherwise it just seems a bit 'off' to me that you believe a person, rodent or trapped cat or whatever is upstairs in your own house and you don't even go up to investigate or at least go outside to catch 'it' in the act of exiting via the window.
Should add that I am speaking from experience here as I have previously posted on here here about the Devon village detached house my parents bought in 1985 did have strange bumps and footsteps that came from an empty upstairs bedroom and which we could never explain. On occasions I heard these when alone alone in the house and would muster the courage to go up and investigate but I'll admit I didn't linger...
