It may not be big but it certainly is clever!
To those kind people who pointed out that:
(a)I could execute the sub without knowing its name - I knew that
(b)That it might not have a name - in my case I knew it had a name but not what the name was.
My problem was that the coderef was being passed in from somewhere else but I needed to get at the subroutine name, not to execute it but to print for debug, logging, etc.
As usual, perlmonks has excelled itself for speed and quality of response ...