Hi Rogissimo,
I didn't know the Strauss connection but I did know it was an opera and that's why I initially included it but, as I said in my original post, I wasn't at all convinced.
I lucked into the actual 14th one, 27d, thanks to a post on here and thankfully so, otherwise I doubt I'd ever have found it - I mean, can you imagine a more unlikely name for a 14a?