The deadline for entering the 2015 Advent calendar competition has now passed. You can see all the puzzles and their answers here.
Thank-you to everyone who took part in the competition! In total, 23 people submitted answers to the puzzles. Every one of these had correct answers to at least 18 of the puzzles. The winners are as follows:
1ScottAll correct at 5:00:18 GMT on Christmas Day
2Louis de MendoncaAll correct at 5:00:32 GMT on Christmas Day
3Alex BoltonAll correct at 5:00:34 GMT on Christmas Day
4Martin HarrisAll correct at 6:15 GMT on Christmas Day
5Linus HamiltonAll correct at 14:12 GMT on Christmas Day
6ZephiAll correct at 20:40 GMT on Christmas Day
7Daniel ChivertonAll but one (5 December) correct at 5:00:24 GMT on Christmas Day
8Jon PalinAll but one (12 December) correct at 5:00:34 GMT on Christmas Day
9Kathryn CoffinAll but one (5 December) correct at 6:28 GMT on Christmas Day
10Félix BretonAll but one (15 December) correct at 9:05 GMT on Christmas Day
I will be in touch will all the entrants in the next few days and I will post pictures of prizes here once they are on their way!
I have already started working on puzzles for next year's (in fact this year's) calendar, so make sure you're back here in December...

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Comments in green were written by me. Comments in blue were not written by me.
@stephan: It looks like the code I wrote to check the solutions were unique contained errors. This might explain why first question was very difficult to solve with logic alone.
Are you sure have unique solutions. See e.g. which gives lots of solutions
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