For a while now I have used a DVD recorder to record things off the TV, mainly before the invention of Sky+ and the like. However one problem that I noticed was that the DVD recorders (and I did try more than one) would never save the aspect ratio of the recording correctly. Playback on the DVD recorder was always fine but another play and it looked either stretched or squashed. Then I found the solution, a little Mac App called myDVDEdit.
Once you have a copy of the DVD from the recorder (I just copy and paste the two folders from the DVD to my local machine), this App allows you to modify the DVD info file which contains all of the information about the DVD including the aspect ratio. The App allows you to change the aspect ratio of the menus and the main video which when I checked was always incorrectly set to 4:3 rather than 16:9 which was the native aspect ratio of the program as it was transmitted.