If u have iTunes, they have almost all of the ones from Masterpiece Mystery!, but if u want the shows from Agatha Chritie's Poirot, then I think u may have to get them on dvd. Hope this helps! :)
P.S.- sorry I don't have a link
Most episodes of Poirot are on Youtube. All you have to do is type the name of the episode into the bar as you do with any other video. For Example - Murder on the Orient Express, like all films watched on Youtube has more than one part. When you search for the episode in question look for a result with 1/9 or 1 of 9 or part 1 of 9, or something along those lines. In the picture shows a result entitled, all aboard - choo choo {1/9} in a red box. that is the result to pick if you are to watch the episode. It is rather good quality.
