Ian, I would think the anonymous poster made a typo or read the name upside down! It would, I assume, be a Wills, made in the 50s - 60s era. I do not have W Wills recorded, rather Wills Engineering, Leslie Ave, North Coburg, Vic.
I discovered these engines just after the firm closed down in 1982. Unfortunately no records or literature was kept. I was told that most of their production went to Pope for their cylinder mowers.
The Wills was a copy of an Italian designed engine made under licence by Trojan. Those little Trojans were quite common in Australia, driving lawnmowers and other small-power devices.
Eric