I've just converted a book from Mobipocket to LRF using Calibre, and there's an odd error. The book is separated into parts, the headings for which normally appear thus (not the actual text, obviously

):
PART 1
A DARK AND STORMY NIGHT
The Mobipocket original is just fine, but the LRF version shows up thus:
PART
1 A DARK AND STORMY NIGHT
Is there a way to prevent this from happening, or to edit the file to put things back the way they should be?