Definitely in parts of the UK, corned beef as morphed into meaning the "hashed/minced" variety that you get in tins, but because the US and Australia have the same meaning of corned beef, it must come from a UK origin.
I wonder if the whole silverside (or whatever) version disappeared during rationing, and by the time that ended, the tinned variety had taken over the name so they had to rename it "salt beef". Certainly I've never seen it called corned beef here, only salt beef.
When I was in New York for work, our colleagues took us to Katz's deli for a corn beef sandwich. My London colleagues didn't look keen, but it turns out they were expecting the stuff that comes in tins. They were pleasantly surprised.
(just had a look at an Australian supermarket, they do have the same stuff in tins, called corn beef, imported from Brazil. They also have the ready-to-cook silverside, for the same price/kg)
