Hi Peter, thanks for the reply.
Yes, it does make sense. In fact, though, I arrived at another solution, which is very nearly part of the SQL Packager product, but which requires two passes.
First of all, I created a package to create a new database, in which I selected just the tables I wanted to update the data for. Instead of creating an EXE at this stage, I just saved the script.
I then edited the script and removed the object creation stuff from the beginning; just leaving the millions of INSERT INTO statements.
Finally, I ran the packager again, and elected to package my edited script as an EXE. I took this EXE to the production database and it all just worked.
One of the problems is that the script generated is enormous, so in reality I had to create three scripts, but even still they were large and finding an editor that could open and save a file > 2 Gb was a feat in itself.
Perhaps this an opportunity to make a feature request? It would be nice if there were the option to exclude the database creation stuff in the tool, to avoid the two passes and the script editing horror. Also, some ability to split temporary files over drives, or specifiy somewhere other than drive C: would be good - I kept running out of disk space.