My 7 year old son recently changed schools, and, according to him, he is having a the same sort of rocky social start as Daisy. The school is much smaller and so are the class sizes, so I thought he would soon find his feet. He is a naturally outgoing little boy and has always made friends easily, on holidays, at the playground etc.
I do think it's harder for children to move schools and make friends as they get older, and I do feel mean about taking him away from his friends at his former school.
We have already spoken to his teacher about this, and we now have two versions of this story. According to his teacher, he was in with a crowd of little boys from day one. He knew some already from Beavers. He certainly does not stand apart in the playground at lunchtimes. Quite the opposite. My husband, who collects him from school in the afternoon, tells me he always has a smile on his face and plenty of children talk to him.
I have asked my son about this. He still maintains he has no friends. He has only had about 6 weeks of schooling, so it is early days. I am hoping what he means is that he has no 'best' friends as yet, not that the class is unfriendly. It takes time to get those special friends, so I am being optimisic. I would love to be a fly on the wall for a day to see exactly what happens.
I think you've been given lots of good advice, so I won't repeat it here. I think it's very important to talk about this to the class teacher, so that she is very aware how Daisy is feeling. If the teacher can find a mentor for her - one of the other children in the class to pair up with her - this might help.
Also, to help her settle, don't let Daisy think there is any chance of her returning to her old school, even if she is still in contact with her old friends there. If she sees her mother waver on this, it might raise her hopes and make her more unhappy in the long run.
Hope this helps