Royal Biographer Angela Levin has warned that Princess Anne’s head injury could be “very serious”, after it was revealed that the Princess Royal is suffering with “temporary memory loss”. Buckingham Palace announced that the Princess had suffered “minor injuries and concussion” on Sunday evening, following an incident involving a horse at the Gatcombe Park estate. In a statement, the Palace confirmed the Princess Royal “remains in Southmead Hospital, Bristol, as a precautionary measure for observation and is expected to make a full and swift recovery”. They added: “The King has been kept close…