A user has a precreated workbook with 12 sheets named jan - dec. Each
worksheet has the names of people in one column and their total holiday
allocation in another column.

When they enter a new name at the end of the list, the name gets replicated
across all worksheets.

However, when they add a new row in the middle of the current list of names
and add a name to the column, this doesn't get replicated across all other
worksheets.

There is obviously some kind of formatting, but I don't know where to look.
Please could someone advise.