Yes, the girl on 334 living 1 mile away would get in before the girl on 423 living 7 miles away.
I have no information as to how far AGGS went out this year's offers. Hopefully someone may be reading this who can chime in with some info. I know there are girls in the current years 7, 8, 9 and 10 who are from further than the 8 mile boundary, but how many, I know not.
You could always consider making a request to the school for the info under the Freedom of Information Act (and then let us know the answer