The product for which Chris has provided the link (out of his vast library) is also available here in the U.S. Some users I've talked to say it works well on their older windows. But the problem of drafts (draughts?) is often not solved since the air infiltration isn't always through the windows but through the framing around the windows. This can be solved, but not this time of year (at least with the winters we have here in the western U.S.) with caulking on the outside.
Try this trick... obtain a small packet of the incense wicks and light one to get a good "smoke" going. When you have a windy day, move the incense stick around the perimeter of the window... it will immediately give you a good indication of the source of the draft...