I am familiar with the set phrase 「言われてみれば」 as a way to say "Now that you say that", but as I examine the phrase further, the phrase structure strikes me as strange. The 〜てみる conjugation is commonly used to say "to try doing something", but what meaning does it give when used with passive verb form; "to try being done" does not make much sense to me.
Maybe one might argue that 「言われてみれば」 is a set phrase so I should just accept it as such, but when I googled around I found that while many verbs yielded zero results when I tried to find their [passive]てみれば forms, there are some verbs, mostly related to speech, that can use this form:
本当に好きだったと聞かれてみれば、本当に愛してたと答えられる。
違う病院に行く、ご事情を話されてみれば良いと思います。
But there are also some verbs that are not related to speech:
愛されて壊されてみれば (song lyric)
お前が轢かれてみれば分かるから、お前で実験してみろよ。
So, in general what meaning does this form give to the original verbs, and in what kinds of scenarios is it used for?
話されて
is honorification, not passive. Well, whether to exclude this as irrelevant may depend on whether you consider this type of honorification as indeed passive with something happening in pragmatics that make it honorific, but probably that is not a standard analysis.言われてみれば
remains a good question.