Try ringing the ACO.
It seems that alot of reminders for payment have gone out to people who have got themselves sorted on other sites and dont need to take up the option given by the ACO.
I think they are giving people until 20th May to pay, so I would assume after then they will release those tickets.
Failing that, as Lawnmowerman says I am sure tickets will be availble on this site in the coming weeks and there will be some available on the gate as long as you get there early in the week.
