The answer is in this post:
[Various simple rename presets - #4 by Leo)
(Find where it says Add spaces around dash (-) characters and collapse multiple spaces: for the relevant part.)
If you've got a working rename preset in the dialog and want to create a button which runs it you can do that very easily:
rename PRESET="Swap Various Artists"(Where Swap Various Artists is the name of a preset.)
Sometimes it's still good to create a button that doesn't use a preset if you don't want the preset cluttering up the list.