I think, to be blunt, the problem is more between you and her dad and your DD is stuck in the middle. Are you together and, if not, do you normally argue over things regarding DD? Is this a parenting power struggle between you? You really need to get yourselves on the same page about what kind of school you want for your child.
Then make an honest list - all 3 of you together - about the pros and cons for each. What does B offer - apart from the peer group - that your DD likes it so much. What does it offer that makes her dad so keen? Now school A - why do you like it more? What does each offer both in terms of classes (subjects, settings), stability of teacher group, extra curricular clubs, trips, residentials etc? How do the schools compare in terms of student support, parent involvement, post-18 placement etc.
Is DD fighting you because she genuinely hates the idea of the school or because she wants to side with her dad against you? If you and dad are apart and she lives with you or together but fighting, this could be her expressing things about your relationship she is unhappy about.
As year 6 progresses do the primary arrange visits up to either school?
You say it is a poorer Ofsted school, but in what area(s)? If it was 'unsatisfactory' for teaching or discipline then I would have concerns, but if one school got 'excellent' and the other 'good' I would not be concerned. What are the local repuations and parental satisfaction levels like for both schools? Which offers the things that are important for your DD - sports, clubs, after school activities etc. How will she manage the journey to the further school if she goes there - 5 miles is a long way in winter and could impact how many clubs etc. she could join or her attendance at other after school activities like dancing or guides? Talk and try not to fight with her, but listen to her concerns and point of view. Answer her questions and points seriously and reasonably. Take her to visit the other school yourself if necessary and possible and take a list of her questions with you to get answered. Most children do settle, even if unhappy at the start, but do you really want to force her into something she doesn't want to do, and which her dad does not want for her either? She may well settle eventually to the school, but in 'winning' the battle you may harm your relationship with her.