Hi, Few months back I tried applying for a LTF AU Zenith+ Metal Card but couldn't get it. However I think my experience will help you
AU Bank currently is spending huge money to acquire customers with good salary and working in good corporates. They're willing to offer their super premium cards (like Zenith+) to such customers as LTF. This is what the Agent told me. He also told me that AU bank has prepared a document of all the corporates and have categorised them in different categories - Super A, A, B, C, etc. Mostly Employees from Super A Companies have very high chances of getting Zenith+ Card Lifetime Free (provided they have good salaries).
Icing on the cake is that the Agent willing shared the list, you can check your company's name in this list. If it falls in Super A Category - you have high bargaining power to make this card LTF.
Au card officers are fraudster , they would convince you to go for smaller variant card and say after 45 days card would be upgraded .
When day comes they don't answer your call and when complained on twitter and on customer care about wrong pratice done they are not interested in noting down complain