Now that the answer to 4270 has been published, it may be of interest to know that a friend of mine who is Swedish, living in Germany and therefore a little out of touch with St Andrew, managed to find a different theme, which worked ingeniously well, though not perfectly. Here’s his surprising take on it.
The dates are one date: 1212 2013, which is the date by which the solution is required. The two numbers forming the cross (following a supposed crossword theme) are: 4271, the number of the next puzzle and 4268, which is the number of the puzzle whose solution was expected to appear with it. 4271 appears as a V shape in the solution, and 2768 as an inverted V underneath it, forming a cross, fitting the cross (word) theme.
OK, “dates” does not carry the same meaning as “data” (being Swedish he thought the word might be able to be interpreted that way), and his theme doesn’t explain the puzzle title, but it’s interesting what patterns the human mind can find if it looks hard enough!