Unfortunately, I don't think anyone answers queries on this forum anymore. I asked this same question back in March and then I contacted them directly. Their response was that the only way to access their database is to do so manually via the web page!!
Its seems a bit ridiculous to allow people to do a batch search and then not be able to download the results.... doesn't make any sense. From my perspective it means that we will no longer be using Metlin data in our research/analysis.
