Yes we know that date of 1967 is not completely correct because the 1960 electric Sunbeam was made in Australia .
I know the Sunbeam Lawnkeeper was very similar in design to the Victa mower and your thinking Jack was Victa made the Sunbeam Lawnkeeper. This made sense because of similarities between Victa and the Sunbeam Lawnkeeper.
I was thinking because Victa had a patent for their handle bars and Sunbeam had a patent for their handle bars ,this would possibly explain Sunbeam making the Lawnkeeper.
I did see a couple of Sunbeam factories in different states and noticing different castings of the Sunbeam Lawnkeeper ,made me think the Lawnkeeper was made in NSW and Victoria.
All speculation on my part about where the Lawnkeeper was made,just wondered if that was a plausible speculation or not.
I was reading in 1960 Turner had a company policy to only make the best, the Turner carpenter's plane in 1960 was made by Turner acquiring the patterns from Pope,Turner redesigned the plane and had a break through in design adding the red cellulose acetate handle, previous handles were wood.