On the basis of what I have so far I don't see how it's possible to partition the grid in a way that is consistent with the preamble. The preamble tells us that the partitioning need not be shown. The implication of that is that it could be shown, and that therefore the existing bars are part of that partitioning. It doesn't say re-partitioned.
However, I have a 5 in the entry for 7d which must be isolated as a solitary prime, and another 5 at the end of 13a. Perhaps that 5 is wrong, but I could find only two squares for 5d that satisfied all the requirements. In one of them the fourth digit was 5, the other 6.