In the song "Anne Boleyn" (With 'Er 'Ead Tucked Underneath 'Er Arm," there appear to be several different mondegreens of the last line of the next-to-last verse.
The line is actually "How the sweet ça* ne fait rien do I know who you are ..."
"Ça ne fait rien" is French for "It doesn't matter" or, idiomatically, "Never mind." It appears to be a French phrase that made its way into British idiom (at least of a certain era).
When I heard the Kingston Trio's recording of this song, I thought they were singing,
"How the sweet Sam Perry, Anne, do I know who you are ..."
Many lyrics websites online have it as "How the sweet san fairy ann ..." (which makes absolutely no sense to me).
Now we have another, "How the sweet Sam Perryham ..."
*In case the French diacritical mark doesn't show up properly on all operating systems, that's a "c" with a cedilla.