I cracked it! :D
Since QTextEdit accepts HTML, <br> tag will make a newline. Here is a piece of code that is different from original post.
@finalText = (str("NAME: %s%sDATE: %s%sNOTES: %s%s" %(tempname,'<br>',tempdate,'<br>',tempnotes,'<br>')))
self.ui.textPrint.setHtml(str(finalText).replace('\n','\r'))@
Might not be convenient for larger pieces of text, but one A4 page (which is my aim) won't be a problem.