‘Never hit a man when he’s down’ is not a motto which applies in business. Apple is in a down phase – by its own standards, if nobody else’s – and the blows are flying. It is under siege from Chinese patent lawsuits, and the old issue of its in-app purchasing policies has raised its ugly head again, with Spotify leading the charge this time. Apple has faced such problems before, but from a position of almost unquestioned dominance of the smartphone space, which gave it the freedom to behave almost as it wished. Now, with iPhone sales slowing and Chinese rivals taking market share, Apple may have to listen harder to its critics. Music streaming service Spotify has sent…