"Conservatrix of Milésien" Habits of mind and feeling, Possibly. But in Ealing With the most bank-clerkley of Englishmen?
It looks like Pound is taking us back into his world of obscure references. Line 182 is a reference to how women from a place called Miletus are supposed to help preserve of converse the traditions of that place. This could be a reference to Pound trying to conserve something of his past through his own poetry.
But in line 184, Pound seems to wonder if this type of conserving can really happen in a modern place like "Ealing,/ With the most bank-clerkley of Englishmen?" The questions seems to be rhetorical, as if Pound is saying, "Of course we can't conserve anything worthwhile in that type of environment." To get the joke, you basically need to know that Ealing is a part of western London that's commonly associated with dullness and the homes of financial workers.
No, "Milésien" is an exaggeration. No instinct has survived in her Older than those her grandmother Told her would fit her station.
When Pound says "her" in line 187, we find out that he actually seems to be talking about a woman from Miletus. He also says in line 186 that calling this symbolic woman a "Milésian" is an exaggeration, since "No instinct has survived in her/ Older than those her grandmother/ Told her would fit her station."
So from what we can tell, Pound says it's an exaggeration to compare any modern woman with one from the world of Ancient Greece. The reason for this is because modern women no longer have the instincts these ancient women once did. Instead, all they have are the instincts and behaviors that their grandmothers told them would "fit their station," or be appropriate for their social class.
In other words, Pound is not a fan of modern women who float around trying to act "womanly" just because their families and their society have told them to act that way. He wishes that modern women could be themselves and reconnect with their true nature. You can definitely see a parallel here between what Pound wants modern women to do and what he wants modern poetry to reconnect with.