I have had 2 girls at/ through a girls school and tbh any reasonable styles are worn. They do adhere to policy for black shoes, no boots, no ballet pumps ( though some have ballet style flats eg clarks ones)
14yr old has 1 pair brogues 1pair Velcro mary janes and alternates them.
Even some year 11s are in clarks/startrite kids. 6th form in low heel courts or brogues ( business dress code)
Hth .i think we maybe get too wound up about all this? Or maybe my kids are just lucky?