The next attempt, even with a 75 second glow and the engine previously running momentarily, took a good 30 seconds of cranking before a single cylinder fired and then another 15 seconds of cranking before enough cylinders were firing to keep it running.

My answer would be: the first attempt has taken a significant toll on the battery making the second heating far less effective

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Retired Marine Engineer
2005 E320 CDI
1987 300 Turbo Diesel @ 300,000 kM going
1974 240 D 300,K Miles when given away gone
1970 200 D gone
1969 190 D gone