Ellie is said to be the subject of Ed's song "Don't," which chronicles a girlfriend (allegedly Ellie) cheating on him with another guy (rumored to be Niall Horan). While Ed has never said who, specifically, the song is about, it sounds like Ellie is tired of all the speculation, and has had her lawyers send out legal warnings to media outlets to quiet the chatter.
According to Dish Nation, a London media source said, "Last week letters arrived on the desks of a number of big news outlets saying that they faced legal action if they claimed Ed's tune was aimed at Ellie and in any way indicated bad behavior. It came as a huge surprise to many, as this story had been written about since May, and no legal notes were fired off."
The source added, "Ed had never denied that Ellie was an inspiration for his work, so this seems a strange response after such a long time. Online there are hundreds of fan and media sites that have gone much further in their descriptions of Ellie. The UK laws on libel are different to the US, so the newspapers there are now steering clear of trouble."