I think this one is actually reflexa. Diplodium reflexa differs from ampliatum in that it is more “bottom heavy” with a more inflated base compared to the longer, more slender appearance of ampliatum. Additionally the sinus is broad in ampliatum where the photographed plant is more acute as in reflexa.
They are all very similar. I had to ask Lachlan Copeland to explain the differences a couple of months ago when he made me aware of D. reflexum occurring on Mt Jerrabomberra.