"Not at Night" No. 12

Anyone interested in British horror from the 1920s-30s will be familiar with the eleven volumes of the "Not at Night" series, edited by Christine Campbell Thomson and published by Selwyn and Blount. I recently was reading Arthur Compton-Rickett's Portraits and Personalities (Selwyn and Blount, 1937). Interestingly, there is a Spring 1937 Selwyn and Blount catalogue, bound in at the rear, which lists twelve books in the "Not at Night" series, the twelfth being a Coronation Omnibus. Clearly a mistake, of course. A WorldCat search turns up no book with such a title, though with George VI's coronation on 12 May 1937 it would seem to have been a possibility. But was there a prankster involved who thought that the idea of a Coronation Omnibus clearly deserved to be marketed as horror?