There was more about this from Miles Kington and a quote from "The True Story of HP Sauce"(Dinsdale Landen and his wife, Jennifer Daniel) :
"The sauce received further inadvertent publicity at about the same period from the late, lamented Marty Feldman. The pop-eyed comedian was making a long-playing record and wished to include a song in the French style with lyrics in that language. Denis King, the composer, imparted this news to the lyric-writer the actor John Junkin, who - remembering his lack of prowess at French from his schooldays - paled at the thought. However, inspiration alighted on his shoulders and, returning from his local grocer's with a bottle of HP Sauce, he presented it to Marty with the suggestion that the French label could provide the lyric. The idea met with great approval, and Marty Feldman sang the famous words in his best Charles Aznavour style, under the title of 'La Sauce HP'."
http://www.independent.co.uk/voices/columnists/miles-kington/art-la-carte-76112.html

Discogs has the year for this as 1969
https://www.discogs.com/Marty-Feldman-I-Feel-A-Song-Going-Off/release/2516554 

https://youtu.be/VIJnP5W_fF8