Finished, LOI 49. Great fun, a proper Christmas Special, except too late. Managed to ignore the badly-placed solutions. It's a pity they had to print the grid so small, requiring close peering at the tiny numbers, when the page has lots of empty space around the minis.
I've grumbled to the Readers' Editor about the non-appearance pre-Christmas (and also Saturday's initial non-appearance of the killer Sudoku online); had a pleasant reply saying she would forward my comment and was looking forward to tackling Maskerade's puzzle herself!