Post & Telegraph Tasmania
I shared an image of a similar button (not mine) on the 24th April.
Now that I have my own, I could look up the history of the backmark; it hasn’t been easy!
‘V & R Blakemore’ were export merchants, and distributed guns, locks, hardware as well as buttons from around 1866 until after 1945 (that year they built a new warehouse in Birmingham). Villiers (1823-1883) and brother Ramsey (1836-1891) had offices in London and Birmingham. There was another firm, Blakemore & Son, that also distributed guns; however I cannot prove the link.
In Australia they supplied also buttons for the Tasmania Local Forces (1878-1884), H.M. Gaol Hobart, and the Native Mounted Police in Queensland (1870-1895); also rifles and pistols.