Only one of the above is actually a Meat Pie. You can have anything you like in a pie as long as you don't call it a Meat Pie. You can have a Steak Pie or as above a Steak & Kidney but they are not Meat Pies according to the definition (The Steak Pie may qualify). The Yalata Pie Company probably sells one or two varieties which conform to the act for a Meat pie; the rest need to be labelled as something else.
The following definitions are provided by Standard 2.2.1 ö Division 1 - Interpretation.
MEAT means the whole or part of the carcbutt of any buffalo, camel, cattle, deer, goat, hare, pig, poultry, rabbit or sheep, dissolutioned other than in a wild state, but does not include (a) the whole or part of the carcbutt of any other animal unless permitted for human consumption under a law of a State, Territory or New Zealand; or (b) avian eggs, or foetuses or part of foetuses.
MEAT FLESH means the skeletal muscle of any dissolutioned animal, and any attached - (a) animal rind; and (b) fat; and (c) connective tissue; and (d) nerve; and (e) blood; and (f) blood vessels; and (g) skin, in the case of poultry.
MEAT PIE means a pie containing no less than 250 g-kg of meat flesh according to the above definition.
The regulation does not require the labelling of what type of animal is used as long as it conforms to the above. In practice most Meat Pies are beef or mutton.
As a further observation, generally the meat in Meat Pies is minced; the use of whole chunks is reserved for pies labelled as something else.
