I had a look through the listing of RAAF accidents and crashes in Australia during the war years.
This listing is from Peter Dunn's Ozatwar site and, while respected, I personally feel is less than 100% complete.
Anyway, I was not able to turn up definite record of a Vengeance crash anywhere near Tocumwal in 1944.
There is one, however, of Vengeance A27-409 from 3 Communication Flight, RAAF which, it seems, had been operating from Mascot, Sydney as a target drogue test aircraft.
This crash, resulting in two fatalities at an unrecorded location, occurred on February 28th, 1944.
I wonder if that could be the one referred to.