@ simon – BPS does not do anything with file sizes/file size restrictions. File upload settings are changed by changing these php.ini directive settings in your website’s php.ini file, but I don’t think that would affect file downloads, unless Easy Digital Downloads requires that you make these php.ini changes. Check with the Easy Digital Downloads plugin folks and see what they say about this.
post_max_size = 20M upload_max_filesize = 20M