That was rather good I thought and definitely on the tricky side with an obvious yet cleverly woven theme.
Keeping track of the months did help with one clue at the end when I had one month missing. 11a ‘middle of month’ is very clever as it could equally be part of the definition even though it’s wordplay.
I did notice that in 2d we saw almost the almost identical clue recently in the Everyman of 3rd January (it was 24a on that occasion).