Complex sentence: Turing calculated the scores for the number of single repeats in overlaps of so many letters, and the number of bigrams, trigrams etc. These were tabulated and the relevant values summed by Banburists in assessing pairs of messages to see which were likely to be in depth.
Split into simpler sentences: Turing calculated the scores for the number of single repeats in overlaps of so many letters, and the number of bigrams and trigrams. Hosgood (2008) 4.2.2 Message Categories These were tabulated and the relevant values summed by Banburists in assessing pairs of messages to see which were likely to be in depth.