If you have been following earlier exchanges on the various threads of this voluminous tale you might remember that at one time it was being suggested that ground speed, or at least some sort of GPS derived speed, could have been used to give the crew some idea of their actual speed in the absence of genuine airspeed data.
In fact the use of the IRS groundspeed as displayed on the FMS MCDU is formally recognized and as such is recommended in several A330 flight crew training manuals. The earliest I can find such recommendation is from early 2005.