According to the German C64 Wiki, a contributor called HTW had a delve into the code for this and states there is no clue at all about who actually wrote it. Maybe somebody in the fediverse knows and can shed some light on it?
This text adventure is from 1987 and was published by Falsoft Publishing, a publisher of magazines and books, primarily the Rainbow series, and it was in the third Rainbow Book of Adventures that this adventure first appeared.