Am I correct in saying that the Digital Boundary Files (DBFs) are not available via the DLI website and that their only mode of access (from Stats Can DLI) is via the DLI’s ftp site?
You are correct. Geography products that are part of the DLI collection (including boundary files) are not available through the DLI website. They are however available through the DLI FTP site.
Some boundary files, which are freely available to all users, can also be downloaded from the StatCan website: http://www12.statcan.gc.ca/census-recensement/2006/geo/bound-limit-eng.cfm The other boundary files which are listed as being for sale ($) on that web page are available on the DLI FTP site.