You are absolutely correct, assaad. While Brett says that it was a Peterson Dublin churchwarden, the current incarnation from Peterson is far different than either that were seen in the series. Also, the original prop was stolen which is why the pipe changes in later episodes such at the one shown in the original post. You can tell that pic is from a later episode by looking at Brett's face. By the time, those last episodes were shot, Brett was undergoing treatment for manic-depressive disorder which he took lithium, whose side-effects include fluid-retention. He tried to combat this by wearing more coats and such. Granada also included his brother Mycroft (portrayed by Charles Gray of 007 & Rocky Horror Picture Show fame) more often to help solve the crimes which were actually solved by Sherlock in the stories.
Sorry. I LOVE this series (in case you couldn't tell by my avatar), and when I read Holmes stories (which is for a few days every month), I picture and hear Brett's Holmes in my mind. This said, I also love the new (modernized & re-imagined) series with Benedict Cumberbatch and Martin Freeman. While non shall supplant Brett as the quintessential Homes for me, Cumberbatch breathes new air into the character and makes him come alive in the context of our modern society. My only negative of the new series that Holmes doesn't smoke which, I think, is a trademark characteristic of the character.
Ok. I'll shut up now.
-Jason