Genius crossword No 247

Thirteen entries have a single letter that is not accounted for in their clues’ wordplay. The enumeration of another seven clues is out by one; their answers must be fitted thematically. Solvers should highlight the theme (19 cells) and rework the grid’s shading thematically (not necessary for online entries).

Deadline for entries is 23:59 GMT on Saturday 27 January. You need to register once and then sign in to theguardian.com to enter our online competition for a £100 monthly prize.

Click here to register.