Ok, here's an example:

As an example take this, and paste into a cell in excel:
="REN value.txt value"&CHAR(128)&"123.txt"
You get a nice shiny € symbol.

To demonstrate the issue:
1. create a file called value.txt, just right click in windows explorer, create new text file
2. same thing again, but rename it to action.bat
3. Now paste the text into the action.bat file (just hit ctr-c in excel and ctr-v in the text file)

you'll have a single statement that reads
REN value.txt value€123.txt
save it and then run it ...
you'll find the file is not called "value€123.txt" as expected but is in fact "valueÇ123.txt"

that's my issue!! I need the filename to show a € in it ...