"Someone managed to jump ahead of me in the queue and pickup 21,700 at 17.5c - I don't know how they managed that when I was at the top of the queue from the previous day"
VERY EASY @Wilma85 ... and possible twice in a day - opening and closing time...
so you are at the top of the queue @ 17.5c and of course the next in line to receive your paycheck FIRST... but at auction time, I can put in a bid @ 18c and GET ABOVE YOU in the queue and still get my parcel @ 17.5c as some nut would put it at sell @ 17.5c (or even lower) to get ahead in sell side at this time... my order gets matched higher than yours as I am ready to big higher...
hope this explains