
> This should be "had been", right? Because "estis" is in the past tense, so "had" not "have", right?
Sorry, I have no idea. :-) This sentence is the original and the Esperanto is its translation so we'd better ask the member who made this translation.

Comparing the sentences in English and in Esperanto I see no problem. Has been done, was done, had been done — all would match.