Thanks to those who helped me yesterday I am now down to the last three. 22ac Writer departs with a letter for the Corinthians (6) l - m - - a 27ac Mean American smashed advertisement about Western (8) t - g - t - - - Looks like tightens but why? 20d Composer of some crosswords met an aficionado (7) s - e - a - - The last letter of this is the penultimate letter of 27ac