Letter is rubbish. They wouldn't have the legal power to enforce anything. We received the same letter today. For a number of reasons the letter is useless,

Letter is rubbish. They wouldn't have the legal power to enforce anything. We received the same letter today. For a number of reasons the letter is useless, and you shouldn't really do anything. 1. It's an email letter, legal letters for any court action need to delivered Registered post, so proof you have received it. This is relatively expensive to do. Especially at the scale they would like to do it at.