Hi there
Have just purchased two new ones for my defender and if you want door seals that fit & do a reasonable job then you will have to go to a main dealer & pay about £40 each for them. The patent ones are cheaper, infact a lot cheaper but they just do not fit as good and if you want to try & keep the wet out, which inturn helps stop the rust then buy the real ones.
Also I had the same problems with the windscreen rubber in that the patent one was made of a harder compound which was less pliable, the OEM part fitted a lot better and sealed well.
all the best Roy