I, too, have those answers in what always seems to be a crossword specialising in weak answers.
Regarding 'passable' - one meaning is that it is just about acceptable. Now take the whole clue - if it was better than passable it would stop being passable and you couldn't 'pass' it - but as it is only passable it won't stop you in your tracks. Sorry that is not very clear, I know, but the clue is not exactly a great one.
Sorry Gen2 and Aquagility I was looking for someone who had completed the puzzle already and agreed with my conclusions otherwise I would certainly have posted the full question
and thank you Salisbury Sir for your confirmation - I thought I must be right I just wasn't happy with it all
Have a good Bank Holiday to you all while I quickly tackle the Herculis