thanks @chanian you have been amazingly helpful!
I’m not sure how i got the wrong code as i just went to the twitter help page and cut and pasted the code provided - the fact is i really don’t have much of a clue about this stuff so its not surprising i went wrong!
anyway, thanks so much for your advice - i went to the link you provided, installed the code, and now have a working twitter follow button - wohooo!