Were i am Steatoda Nobilis and its biting partner in crime Steatoda Grossa are very common spider's. Were there is one there is usually more and were you see a cobweb** it usually belongs to one of them.
** gates, window ledges, shelfs, etc. I thought for some time that they would only weave webs of the ground but i saw a Grossa in a "ground" web behind a locker a few day's ago - im sure a house spider will come along and challenge it sooner or later
