Coles and some IGA's sell Mcloughlin's Irish bacon, black pudding, sausages and boiling bacon or bacon steaks. I love gammon too and this is the nearest I've found to it here. Not cheap tho, I've just paid $9.83 for a joint weighing 762kg and $9.17 for 470kg bacon. It is nice tho. I slow cook the joint and make soup but I guess you could roast it.
They call it pickled pork here and it is not nice, tastes like pork in vinegar nothing like gammon!
if anyone else knows where you can get proper English gammon I too would be very interested to know!