We moved into a Victorian terrace house over a year ago- the survey didn't raise any concerns but recently we've noticed that the floor in the living room bounces a little when we walk across it - the bounce is localised to one part of the living room - how can we distinguish loose floorboards from something structural (e.g. Joists).
Just to make sure it isn't something more sinister, lift a couple of floorboards in the area and just check the joint for dry rot. This will put your mind at ease. When replacing the floorboards, use wood screws instead of nails. It will stop them from coming loose again.