"The instructions state the bin was "the same type as fitted to the Australian Cruiser tank Mk1 `Sentinal'", which may indeed be the case, however, some cursory internet research reveals that identical bins are fitted to surviving Staghounds in France, England and the United States, which indicates it is a standard, (possibly post war) T17E1 item."
The key there is "surviving vehicles", the ones you are looking at are all ex-Australian vehicles bought by overseas collectors and museums.
Unless you've seen period photos with the bin fitted?