Well that made progress. There is a bruit force method, but it means eating up a bunch of bandwidth in the process.
Delete the DLC package folders first.
Run a database repair.
Exit.
Start again and at the Launcher redownload your purchased items.
This will reset everything and all content will be downloaded.
Be warned: A validation process will run afterwards as the data gets synched into the database again. This can cause stuff not to appear in the menus in Surveyor until all is done, and may cause a performance hit.