This what the email said: "Trove API Terms of Use specify that developers may access metadata only and do not provide extended rights. We consider the use of an API to extract and save full text as being in violation of the Terms of Use."
Which given that the API provides full text from newspapers, journals, books etc means that using the API is a breach of the API terms of use...
In any case, I didn't use the API to get text from the NED periodicals, I downloaded the PDFs.