The relevant bits...
"... from Sunday 2 July,... usage meter will stop recording your usage... System upgrade... Which means for a limited time we are unable to measure your data usage... Your data allowances are not applied for the duration.
In the week starting 28 October the usage meter will begin recording usage again... Usage limits will reapply"
Woohoo, so unlimited usage for 4 months?? Glad I just bought a new 2TB drive!