DD strongly geared her Personal Statement to the subject she wanted to study. At Edinburgh she could only study that subject as a Joint Honours - funnily enough Edinburgh were the first to make her an offer and she actually ended up there.
Most (not all) unis are very helpful if your DD wants to phone and check anything - it's also a useful way of chosing your final five in our experience. DD phoned three with the same question, two very helpful, one passed her around a few departments and no one could help - she was promised a phone call back which never happened.