Well... as it turns out posting on here did the trick - after a final try (I logged off in front of the ghost in frustration, posted here and thought "one more try before bed then") I logged on in front of him, at which point he decided to talk to me and the quest is done.
Maybe I had the wrong perfume on or something.. either way - all sorted now.
Maybe I had the wrong perfume on or something.. either way - all sorted now.