Or why not issue it all as one instruction? As a pilot, when I am told to go around, I assume there is a safety issue and immediately initiate action based on what is in the call, even before I acknowledge the instruction. While the phaseology might not resemble word for word what is in the book, would have an instruction "XYZ Go-Around, Immediate Right Turn Heading 180 Climb 3000ft" not been sufficient? Everything is then contained in a concise message. I would hope in a critical situation the pilot would begin go-around action before even thinking about reading back the instruction, even in busy airspace such as Heathrow. Once the aircraft is not heading towards the ground the call can be acknowledged, then the checklists can be done...