30 Sqn's ORB for the 5th March 1942 reads "All available personnel of main party on board HMS Indomitable working throught the day and night assembling Hurricanes in Aircraft hangar and by late on 6th March SEVENTY aircraft had been assembled"
This is where John Hamlin would have got his figure from for Flat Out.
The ORB goes on to read - 6th March 1942 "20 aircraft flown by pilots of 30 Squadron took off from the Aircraft Carrier succesfully. One Hurricane piloted by Sgt Whittaker developed a glycol leak, he decided to return. HMS Indomitable assisted by steaming into the wind and increasing speed. The crash nets were raised, Sgt Whittaker after making one dummy approvach landed his Hurricane (without arresting hook) bringing it to a halt some fifteen yards from the crash barrier.
Six additional 30 Squadron pilots flew from the Caarrier at 1600 hours landing at Colombo at 1615 hours.
Hope this helps in some way even though it doesnt exactly answer your question.