I don't think we should consider the nature of the word that comes after UNIT in this decision. Regardless of it being a noun, an adjective, a verb, a pronoun, or whatever else, the simple truth is: "UNIT" remains a prefix. It should not affect our decision, as it definitely would not affect the naming of the story in a Torchwood or Doctor Who audio.
If an anthology was refered by Big Finish as "Doctor Who: Silenced" or "Torchwood: Silenced", what would we name it (keeping in mind what we've done for all audios and anthologies so far)? We would name it's page "Silenced (audio anthology)". So why would UNIT be any different.
Look at Broken (audio story). No one here would think of naming this page "Torchwood: Broken", even though the "Torchwood" prefix is stated both on it's oficial page and on it's cover.
UNIT plays the exact same "role" on names as Torchwood: to give buyers a general idea to which range the story/anthology belongs. Nothing else.