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Thanks to both Toorak (who gets it by a whisker) and dannyk.
Finding the correct grid position is anything but simple, with 14 5-letter possibilities, of which maybe 6 can be eliminated immediately.
After some serious frequency-counting, it becomes clear which numbers represent A & E. Which is which can be determined by finding somewhere where the two numbers are adjacent. (EA is much more common than AE.) E is also much more likely to end a word than is A.