@drMerry - yeah we crossed posts again. I have no objection at all to changing the regex or matching algorithm if you have a better one - as I said above I did not write that part of the code nor have I ever investigated all the variations. I just wanted to offer an easy to use wrapper around something that people could use within Calibre rather than running external scripts etc.
So if you are willing to do the investigation can come up with an improved version that isn't noticeably slower than the existing one then by all means please send it to me. PM me your email address if you like and we can swap info there. My main concern would be false positives as you say from telephone numbers or similar. If you come up with something that you are confident will not suffer from that issue then I'm sure everyone would be grateful for your effort.