"Yeah, exactly. It is where the Srum were founded. It used to travel but fueling that ancient thing must have been too much for their coffers to fund. Or it broke. Either way, it orbits a dead, nameless dwarf planet. I guess you could call it Srum too. I can give you the coordinates..."
A bit of palaver with the Council might be necessary, yes. Remain aware of the fact that your mission is not official.
As it is, you are done here on Nar Shaddaa. Marl did not deal directly with the Kylugo Srum or the Tyr-sen and cannot be implicated in their dealings. He is an independent slaver, and now an arrested one. He gladly shares with you the coordinates to the uncharted, uninhabited dwarf world that the Seat of Srum is in orbit around.
"If you need anything else, feel free to ask!" Marl says. "AND to lower my sentence, whatever it will be."
It is actually Edula that sends men to clean up Marl's operation on Nar Shaddaa, at the behest of a powerful local Hutt. She does make an appearance herself, but her rat-faced servant Harfer does. He seems pretty pleased with how things turned out.
All that remains for you to do is return to your ship, contact the Council, and plan how to tackle this space station of slavers.