Film sounds a bit dated. What would it cost, I wonder, to have a copy of the book (I asume you have one) scanned digitally and recorded on a CD?

Two thoughts came to mind with your post:
1: A book that is 15 yrs old may well need some major updates. Are you willing to do that before trying to sell to a new publishing house? And put it onto a new media.
2: What happens/has happened to the film? Will they certainly destroy all copies of it? I assume that no one has copied it? Could illegal copies be made if you do not buy the film back?

"I am informed the film will be destroyed unless I buy it by paying shipping from China -- about $250"

Don't bother: they are trying to get some money out of what is basically trash ... what you will get is scratched, bent, badly stored sheets of "film" that are used to make printing plates with. Not only will it only work for certain printing companies (those who still use the outdated method), unless they have been stored in impeccably clean conditions, they will require more touch up on the scratches than they are worth to be usable again.

If you want to get the book going again ... take one of your copies and UPDATE IT ... look at it as the second, revised and expanded edition. Then sell the new version.

Katy -
Yes the film could be used to make unauthorized copies ... if the person who had the film also had access to a multi-thousand dollar press, plate making equipment, and an experienced printing staff. Possible, but not worth the hassle. They are probably making more money printing illegal copies of Harry Potter books.

Many thanks for your advice, all. I have decided to bag the film, and, if I get the time, to aim at a second edition with some new and expanded text. I love the old book, but don't we all love our kids?