I hope you guys aren't buying the wrong GS size on UK sites. The UK to US size conversion for GS sizes isn't the same as men's.
Here's the conversion for GS sizes:
[TD]UK[/TD]
[TD]US[/TD]
[TD]3[/TD]
[TD]3.5Y[/TD]
[TD]3.5[/TD]
[TD]4Y[/TD]
[TD]4[/TD]
[TD]4.5Y[/TD]
[TD]4.5[/TD]
[TD]5Y[/TD]
[TD]5[/TD]
[TD]5.5Y[/TD]
[TD]5.5[/TD]
[TD]6Y[/TD]
[TD]6[/TD]
[TD]6.5Y[/TD]
[TD]6[/TD]
[TD]7Y[/TD]
Also, some UK sites don't differentiate which UK 6 they have available, so you can be ordering either a 6.5Y or a 7Y.