Hi Geoff,
I guess you got the info from the RLC Museum in Deepcut? Usually the records show that when struck off, where it was disposed off, ie disposal depot, like Ruddington, etc. My feeling is that it may have been transfered from Army "ownership" to an authority involved in the bomb testing in Australia, the timing would be about right. Then it was disposed of locally. I have seen a photo of the Centurion on the way to or from Maralinga (I think) with a Q4 in the background, will have to see if I can find it.