JD_Toims - 10:38 pm on Sep 17, 2013 (gmt 0)
I don't see where adding Options +FollowSymLinks to the top of the .htaccess has been tried, so that's probably a good idea to test just to see what we get out of it.
Note: Try the preceding in the test directory's .htaccess again to keep from impacting the whole site and if you receive a 500 server error when requesting your-old-site.com/123-testing/something-else.ext it would seem like it's a permissions issue even though Options All was the default until Apache 2.3 and since then FollowSymLinks has been.
[Edited: I meant Options in the second paragraph but typed AllowOverride the first time -- Glad I got to it before Lucy24 made it by. Not sure how I'd live that one down lol]