Hi MummyGilly
There is a book called 'Audition Speeches for 6-16yr olds' by Jean Marlow. It's weird I actually thought I'd already posted this but appears not

Does your DD do LAMDA exams, if she does I'd be inclined to use her last exam piece. It's always so much easier to do something you know well. As an aside though you may want to also look at something contempory which reflects kids today, etc. I have no ideas for this part as my DD is 10 and when asked does Anne of Green Gables or Alice in Wonderland or Wizard of Oz.......these, however, maybe too young for your daughter!! Most of all I think your DD just has to be herself and be confident. They may also ask her a few questions about herself, what she likes, role models etc.....just don't be phased