Syntax for New Name with Regular Expressions

Is it documented anywhere what expressions can be used in the New Name field when doing a RegEx rename?

You can use \1 \2 etc. of course but I am having problems inserting a literal \

\1\2\3\ \3 \2 \1 produces a literal \ followed by a single space

\1\2\3\3\2\1 produces a literal \3

How can I produce a literal \ not followed by a space?

You use two \ together.

\3 turns into a literal \3 because it is \ followed by 3: the \ turns into a literal \ and then the 3 that comes after it is just a 3.

Use \\3 to get a literal \ followed by the 3rd match.

Thanks. Yes I wanted \\3

Can I ask you another question?

I now have a rename set up as follows:

(\d\d\d\d) (\d\d) (\d\d)(\s*)(.*)
\1\2\3\\3 \2 \1 \5

If I select a number of files in a folder and do this rename then it does what I want -
i.e. if I have a file named 2010 02 03 TestA
and I apply this rename, it creates a folder named 20100203 with the renamed file 03 02 2010 TestA
within it

However it I select a high level folder and tick the "Rename files in selected sub-folders" option it renames the files as e.g.
03 02 2010 TestA

but it does not create the subfolders e.g. 20100203

Turning on "Rename files in selected sub-folders" disables the ability to move things around (actually, the ability to do that at all is an accidental feature, albeit it a very useful one, so it's not really disabling it; it's more that the same accident isn't in both modes).

If you put the lister into Flat View mode (or use the Find tool to get a list of all the files below the folders), then select all the files and rename from there, you can do the same thing without having to turn on "Rename files in selected sub-folders", and thus be able to move things around