Ahnold
The Former Governator
Though yerssot has done an excellent job, I suppose that we will never find out the full answer to this question; after all, the actress playing Bunt {Ilse Steppat} died so soon after "OHMSS" was released that the producers couldn't have possibly had time to come up with a fully formed plot outline for "DAF" that included Bunt. And it makes perfect sense, given what yerssot has said, for them not to recast the role. Aside from perhaps not doing so as a mark of respect to Mrs. Steppat, re-casting the role might well have confused viewers, especially if Bunt would have only made a brief appearance in "DAF"; bearing in mind that most viewers were proabably not that familiar with the character anyway, casting another actress in the role would've just meant more time wasted explaining just who this woman is ...
It makes you think, though - wouldn't it have been strange to see Irma Bunt disposed of so unceremoniously within the first five minutes of "DAF", as yerssot suggests the case would have been? I mean, c'mon - this is the woman who murdered James Bond's wife ! They surely couldn't let her off the hook so easily! Had the actress still been alive, they really should have kept her on as a major villaness for "DAF" as well ...
As it stands, though, Bunt's absence from "DAF" only serves to increase her notoriety. After all, she's not only the woman who murdered James Bond's wife, but the person who got away with it too. And for that reason, she'll always have an enduring legacy; yes sireee - no stoopid death by chimney stack for THIS member of SPECTRE 😛 ...