Hi from Australia too.
Over here there is a range of dwarf Lemons and Limes grown from cuttings.
Basically they look like a branch coming out of the pot. Usually called Lotsa Lemons or similar.
Also there are Dwarf grafted types, on either Poncirus trifoliata rootstock or Poncirus var Flying Dragon.
Flying Dragon is a dwarfing rootstock, standard Poncirus is semi dwarfing, at least in the early years.
With both of those grafted types, you should see a distinct rootstock trunk with different bark to the lemon on top.
So it could be either of the three above.
If you post a pic, it should be easy to tell. Mainly need to see the 30 cm or so from the soil up.