mscroggs Advent Calender Number 2

As with last year, mscroggs is hosting an advent calender of maths puzzles with a new puzzle each day. Putting together your answers to the 25 days you have all of the information you will need to solve a meta logic problem. He ran it last year and it is very high quality (and quite hard: I spent some of Christmas morning last year trying to sort out my couple of missing answers to no avail). In the absence of a GCHQ challenge this Christmas and now that the Ritangle competition is over, this fills my need for Christmas Seaon Puzzles perfectly.