I compiled a list of squadron associations when I was organising V Force Reunions, and as far as I know there is no current 12 Squadron association.
However there was a combined 12 and 626 Squadron association which went under the name of the Wickenby Register, and there are contact details for the surviving members of that association here.
RAFWMC - TheHistoryofWickenby
Not sure how current that is, but it's the best I can do. Good luck helping this lady - it's a touching story.
TTN
Oops - beat me to it by one minute
rolling 20!