The version of DM6-BN215 listed in my 1963 VAOS is 40308H as opposed to 40308A for the RAF although that is 9 years earlier it just says Austin 1 Ton 4x4.
I can't find 40147 listed in 16E.
My 1953 Austin Parts List WO Code No.17735 quotes:
DM6-BN125, 40308A - vehicles without wireless
DDBCH9A, 40309A -screened for wireless vehicles