Great. All sorted. Went into view and ticked the option to show file name . Cheers.I don't have Windows 11 so I can't check but it's possible file extensions are hidden by default if they're known (i.e. there is a program associated with them, which in case of .txt files, there would be). You may have to make them visible first.
Here is how! Do that and you should see the .txt extension of the files. Now just "rename" the file and take that .txt part out of the name.