As bananabean suggested, it's actually to do with the clashes, so whilst the bar pattern exhibits symmetry, some of the grid entries are shortened versions of the answers. For example, the 12 letter across answer that starts in a different column is shortened to a 5 letter word by creating a gap in the word where 8 letters are removed. The gap coincides with a similar gap in a crossing down entry and is replaced by one of the 6 letters of the author's surname to create the final entries. The 14 letters removed from the two answers can be rearranged to the titular character. This also explains why there are more letters in answers than cells available in the grid. It was easy enough to work out where the 6 gaps must be once the bar pattern was established, but this did depend on finding the quotation in order to establish the indexation.