Thank you for all of the input, what a wonderful collection of brains we have on the MLU
It makes sense to me that they are from AFV's due to the "FV" number and being so close to Puckapunyal the hunting ground of the Centurion, Saracen, Ferret etc. The last inspection tag on them is dated 1955 the right time frame for these vehicles in Aust service.
Cheers.