It was explained by last week's crossword that there has been a continuous series of crosswords in the magazine for several years but when it was renamed as the Inquisitor it started from number one, but in effect there have been 1106, hence this week's one is 1107.
As you can imagine, Inquisitors published over the holiday period had to be put to bed well in advance, and someone at the Indy must have neglected to advance the closing date by one week. It's not something I normally have to check, being primarily concerned with the puzzle itself. I will do so in future!
I've made sure that entries are accepted up to what should have been the closing dates given.