There is availability on 23, 24 and 25 December. In Premium too, so about 6900 points + something like 50 bux. On 25 DJ849 is operating with the A330 so an excellent flight to redeem points for.
Few weeks ago I booked for a friend at 2 hours prior to departure, PER-MEL.
Everything can be done online through the velocityrewards website, you do not need to call anyone! Just go through the process, and you will be asked to enter the traveller's details prior to the final page where you use the slider (to minimum 6900) and enter credit details.
Too easy, I am not sure if I misread your question?