I don't believe Big W came onto the scene until well into the early 80s. That mower base is from the 70s and has the old Woolworths logo that was never used with Big W. I think this mower was probably sold in select Woolworths department stores, the ones with the concertina wooden framed doors that so many had. I always saw that as their signature feature.
Hello
Gadge and
MowerfreakThere is clear evidence that Big W appeared here, on these shores, in ...
1964.
https://en.wikipedia.org/wiki/Big_WG'day CyberJack,
The article you linked to suggests this store that opened in Tamworth was peculiar to that town only, perhaps as some sort of one off experiment by Woolworths at the time.
Woolworths probably later decided to use that name to take over the role of Woolworths Variety stores as a new chain of stores many years later in the 1980s. The article also mentions that Woolworths Variety stores continued to operate concurrently to Big W well into the 1990s as the new concept chain was phased in to take over the old.
The Wikipedia article also says:
The Big W chain grew out of Woolworths Limited's original Variety stores, which carried a small range of general merchandise products.. This further backs up my position.
I believe these entry level mowers were indeed sold at Woolworths Variety stores. Quite amazing, the range of store brands Victa released. Betta electrical was another I can think of. Norman Ross, was no doubt another. Oh chandlers too!