It sounds to my ears like, for the most part, they actually kept Joan Sims' original voice for the witch.
- Update - Yep, Joan Sims is credited, along with Mona Marshall who did the extra lines. (Toni Collette in the Miramax edit.)
That comes in very handy, as the witch audio is awful. I'll go ahead and replace it with the Princess material where possible.
Oh .... on the subject of swearing in this movie .... I hadn't really noticed before, but one of the Brigands clearly says "Get your ass down. Get it down."
Nice.
The Nurse was allowed to say "ass" in the script, so I guess that makes it official. Along with the gag where Zigzag stops himself saying the "f" word.
Brings it one step farther away from Disney.