You have to quote "2010" over the phone..
Their number is 134 STA
Didn't post this as a voucher, as you cannot use it online.
The email reads:
OUR WEBSITE WAS DOWN
WE WANT TO MAKE IT UP TO YOU
We'd hate to kick off Feb 2010 with an inconvenience!
So to make up for our website being down yesterday,
we'd like to offer you a $20.10 travel deal.
Simply call 134 STA & quote the promo code: 2010,
to receive $20.10 off your travel purchase*.
This offer is exclusive to you by calling 134 STA,
when you phone us before 2pm this Saturday 6th Feb.