"I Should Have Known" written by Cahn/Ridley

Anyone know if this is a cover?

This was written by British composer Walter J. Ridley and American lyricist Sammy Cahn. I can't find any other versions of this, but I find it a bit odd that an original song would be relegated to the flip side of a cover ("Whispering Grass" by Don Estelle and Windsor Davies) and the second-to-last track on the B side of an album (Sing Lofty) - especially given how famous Sammy Cahn was.