How do I get to Grunting Fen?

I just started off on my first Scientific Expedition, and once I get across the Unterzee, I only see the options for Bullbone and Corpsecage islands, both of which I’ve done now. I know from the wiki that there’s a third island to explore on an expedition, Grunting Fen, but I am unsure of what unlocks it. [li]

It’s not in the Broad Unterzee but the Sea of Voices, near Polythreme. You’ll need a Screaming Map to find your way there.

It is in the Sea of Voices. You need a Screaming Map to get there.

Many thanks! Back to London I go to complete that quest. Cheers, all.