I just did a Google search. It's amazing how many parodies there are of Monty Python and the Holy Grail:
Arthur: O Knights of Ni. We have brought you your shrubbery. May we go now? Knight of Ni: Yes, it is a good shrubbery. I like the laurels ...
"Oh, Borg who say "Ni" > We have brought your shrubbery > May we go now? You now must defeat the Q Continuum with... a _herring_! > With a ... " etc.

But I only found musical references to Ian Benzie, no other recordings or web pages with the words "may we go now"
But I'd still like to hear the song!