I'm trying to find an earlier thread on this subject but the search doesn't appear to be working.

As far as I understand, the harp thing is essentially an "urban myth" because:

(i) the declaration was never actually enacted (it was simply a declaration, even according to Grattan Flood).
(ii) it's unlikely that Elizabeth knew anything about it anyway (it was made in 1603, and she died 24-03-1603, and it was made in her name, not by her).
(iii)Elizabeth retained and paid an Irish harper until her death.
(iv) there is no evidence of a single harper having been hanged because of it.

I know this information is "common knowledge" on the internet. If you find the original thread, I believe there's a little more information.