Yep, I would say it was one of severins, in the Uk at least, possibly Black Lamp would have also been one of the first as well.
Would be nice to see if anyone does know, Im sure they do..
edit:
I done a quick search and found these for 1985 and none for 84
Mindscape 1985 Amiga OCS
Brataccas *$# Psygnosis 1985 Amiga OCS
Cutthroats * Infocom 1985 Amiga OCS
Deadline $ Infocom 1985 Amiga OCS
Enchanter $ Infocom 1985 Amiga OCS
Infidel $ Infocom 1985 Amiga OCS
One On One Electronic Arts 1985 Amiga OCS
Planetfall (Planet Fall) $ Infocom 1985 Amiga OCS
Sorcerer Infocom 1985 Amiga OCS
Spellbreaker $ Infocom 1985 Amiga OCS
Starcross $ Infocom 1985 Amiga OCS
Suspect $ Infocom 1985 Amiga OCS
Suspended $ Infocom 1985 Amiga OCS
The Grail * Microdeal 1985? Amiga OCS
The Hitchhiker's Guide to the Galaxy *$ Infocom 1985 Amiga OCS
The Witness Infocom 1985 Amiga OCS
Ultima III: Exodus * Origin (Banjo) 1985 Amiga OCS
Zork I: The Great Underground Empire $ Infocom 1985 Amiga OCS
Zork II: The Wizard of Frobozz $ Infocom 1985 Amiga OCS
Zork III: The Dungeon Master $ Infocom 1985 Amiga OCS