Bit of an odd bug, this.
I'd killed poor old Inspector Daton as promised and got my reward. When I went back to the Sea's Bounty to talk to Thumb during the Black Lotus mission, who should be chilling by the bar, but Inspector Daton. Some kind soul obviously took him to the temple for a resurrection, so I kept my head down and didn't speak to him.
I have a few mods on this runthrough, so not sure if this is down to a conflict, or just a matter of not removing the Daton spawn from the tavern when you spawn him outside. For reference, though:
// Log of Currently Installed WeiDU Mods
// The top of the file is the 'oldest' mod
// ~TP2_File~ #language_number #component_number // [Subcomponent Name -> ] Component Name [ : Version]
~SETUP-ASCENSION.TP2~ #0 #0 // Ascension v1.41 (requires ToB)
~SETUP-ASCENSION.TP2~ #0 #3 // Tougher Gromnir (optional, requires ToB)
~SETUP-ASCENSION.TP2~ #0 #4 // Tougher Illasera (optional, requires ToB)
~SETUP-ASCENSION.TP2~ #0 #5 // Tougher Yaga-Shura (optional, requires ToB)
~SETUP-UB.TP2~ #0 #1 // The Suna Seni/Valygar Relationship
~SETUP-UB.TP2~ #0 #2 // Kalah and What He Was Promised
~SETUP-UB.TP2~ #0 #6 // Restored Crooked Crane Inn
~SETUP-UB.TP2~ #0 #17 // Corrected Character Names and Biographies
~SETUP-UB.TP2~ #0 #21 // Throne of Bhaal Minor Restorations
~SETUP-UB.TP2~ #0 #24 // Sarevok's Remorse
~SETUP-UB.TP2~ #0 #15 // NPC Portrait Restorations
~ASSASSINATIONS/SETUP-ASSASSINATIONS.TP2~ #0 #0 // Assassinations mod for Baldur's Gate II, v2
~SETUP-EDWINROMANCE.TP2~ #0 #0 // EdwinRomance
~SETUP-EDWINTOB.TP2~ #0 #0 // Edwin Romance ToB
~SETUP-EDWINTOB.TP2~ #0 #1 // New ending for Viconia Romance by Laufey
~RE/SETUP-RE.TP2~ #0 #0 // Aerie, Anomen, Jaheira and Viconia React to Romantic Encounters
~RE/SETUP-RE.TP2~ #0 #1 // Storms and Lightning, by berelinde (Weathermistress Ada, adult content)
~RE/SETUP-RE.TP2~ #0 #2 // Aimi's Magic, by berelinde (adult content)
~RE/SETUP-RE.TP2~ #0 #3 // Anishai's Deft Hands, by cmorgan
~RE/SETUP-RE.TP2~ #0 #6 // Bodhi's Allure, by Kulyok (adult content)
~RE/SETUP-RE.TP2~ #0 #7 // Trademeet with Guildmistress Busya, by magrat
~RE/SETUP-RE.TP2~ #0 #9 // Chanelle's Gifts, by cmorgan (adult content)
~RE/SETUP-RE.TP2~ #0 #11 // Cyric's Test, by Kulyok
~RE/SETUP-RE.TP2~ #0 #13 // A Lonely Dryad, by Kulyok (adult content)
~RE/SETUP-RE.TP2~ #0 #22 // Ilona, a Merchant's Daughter, by Kulyok
~RE/SETUP-RE.TP2~ #0 #24 // A Night with Lais in Imnesvale, by Kulyok
~RE/SETUP-RE.TP2~ #0 #28 // Mira's Special Stock, by berelinde
~RE/SETUP-RE.TP2~ #0 #30 // Rebecca the Gypsy, by Kulyok
~RE/SETUP-RE.TP2~ #0 #35 // Dreaming of Sendai, by Kulyok
~RE/SETUP-RE.TP2~ #0 #36 // Sheri the Bardess, by cmorgan (adult content)
~RE/SETUP-RE.TP2~ #0 #37 // Solaufein in the Lust Chambers, by jastey
~RE/SETUP-RE.TP2~ #0 #41 // Isabelle's Fears, by gertjanvh
~RE/SETUP-RE.TP2~ #0 #42 // Anne's Rescue, by gertjanvh
~RE/SETUP-RE.TP2~ #0 #43 // The Queen, by Domi
~RE/SETUP-RE.TP2~ #0 #45 // Rehearsal with Chandra, by Western Paladin
~RE/SETUP-RE.TP2~ #0 #47 // A Chat with Viekang, by magrat
~SETUP-NPCFLIRT.TP2~ #0 #8 // Viconia Flirt Pack for SOA
~SETUP-NPCFLIRT.TP2~ #0 #10 // Viconia Flirt Pack for TOB