Within Find & replace there is a ‘regular expression’ option in the more options. To non-techie users what this does is probably not obvious. an explanation (maybe on hover) or a different name for this option would be useful.
Try this extension (http://extensions.libreoffice.org/extension-center/alternative-dialog-find-replace-for-writer). It is much easier to use than the built-in version.
About renaming it: NO it is around for a long time.
One must use caution with the “Alternative Find and Replace Dialog” though; it sometimes causes loss of formatting and has performance issues. Furthermore, it appears to be unmaintained.
Hi @Nickmdowson,
As @horst mentions, the term “regular expression” has existed for a very long time; further, the term means something very specific in terms of abstractly matching a search pattern.
A mouse-hover explanation or additional references in the Documentation are a definite possibility. If you had a question about this particular piece of LibreOffice and chose to ask us about it, chances are good that another 10 people had the same question and didn’t get around to contacting us. Please consider filing an enhancement bug and providing a brief explanation as to how you suggest that we better-inform our users (tooltip, documentation, and/or ??). Don’t forget to mark your bug as an ‘enhancement’. The QA team will be happy to help you triage your feature request in the bugtracker.
Please post a link to any bugs you file in a comment below using the format “fdo#123456”.
Thanks!
There’s a "Help" button in the Find & Replace window. 
Enable 
Regular expressions,
click on “Help”.
That will open → this “Help” item
Regular expressions
Allows you to use wildcards in your search.
List of Regular Expressions
BTW:
I do prefer the above-mentioned extension “Alternative dialog Find & Replace for Writer”.
→ Screenshot
LibreOffice v4 upgraded Regular Expressions to more standard compatible way of regular expression. So this user guide may help: