I think the answer is yes.
After last week's stall, I finally took my heroine out of her usual environment for a trip to a new and exciting world, and hey presto, the words started to flow. I'm now sitting at just over 45000 words with an anticipated finish date of Friday. Who would have thought it last week?
There's a pretty major plot hole I've managed to skirt around during this first draft, and that's going to need a lot of work during revisions. But I think finally, after three and a half weeks, I now know my hero and my heroine well enough to get this story finished.
Wish me luck...