Heavy suffix not commonly used in our aviation backwater, even by North American pilots.
Heavies tend to fly in A, B or C airspaces, and occassionally in E airspace. So is there really a need for the suffix heavy while in A, B or C airspace? I think not, otherwise all those 737s and A320s would be announcing Medium to alert the lighties they are a medium.
It might still be in CARs, but so is the 20 minute longitudinal separation standard, which hasn't been used in Oz for over 10 years.