Thanks. I noted in my comment the option to re-add it to the toolbar, but everyday users can't be expected to know this is possible or how to do it.
Nor should they have to, given that mail retrieval is something that everyone can logically be expected to do if they're told they were just sent a message.
People who want to click a button to skip waiting for the next mail poll time (and who even know what that means!) probably can be expected to know that just about every toolbar can be customised.