He is apparently mounted on a jeep rather than a horse to reflect the change in technology during his years of service in the army.
(Note, the plaque is smaller than shown)
Plaque reads: ' Field Marshall Sir Thomas Albert Blamey
G.B.E., K.C.B., C.M.G., D.S.O., E.D., P.S.C
1884 - 1951
Australian Military Forces 1906 - 1951
General Officer Commanding
Australian Imperial Forces 1939 - 1942
Commander in Chief
Australian Military Forces 1942 - 1945
Commander Allied Land Forces
South West Pacific Area 1942 - 1945'
Submitted by: @IanThorp