From the Annual Report for the year ended 31st Dec 2014 "In...

From the Annual Report for the year ended 31st Dec 2014

"In October 2015 there will be an opportunity for convertible note holders to redeem their notes. The carrying value of the convertible note liability is $50.686 million, however, it is the opinion of the directors that the notes will, once again, be rolled over and therefore the cash required to redeem the notes will not be required. Should the convertible notes not be rolled over on their redemption date, there is significant uncertainty as to whether the Group will be able to continue as a going concern unless additional working capital to repay the convertible notes can be secured."

The noteholders don't have to convert - they can ask for their money back, and, I imagine, appoint receivers if they don't get it.