Unfortunately, the world isn't coming together on a singular format. It'd be nice if it did. It's more than just firmware.
The other thing to consider is the region codes for movies and supported devices. Like I said, not to discourage, but moving any set from one to another still leaves the possible risk of something not working properly as a result.
If you want to try using a firmware from a different region (or worse, an "unlocked" one), I'd really *really* recommend against that. I've seen enough posts here where people accidentally install the firmware from a different region, and it really screws up the TV, and depending on the region, voids the warranty. And Samsung UK Service may not work on a AU TV, and this is discovered with the model/serial in the event it was to break. If you're still interested, do some research to see if it can be covered. I could be wrong, and it wouldn't be the first time.
It's your set, and your decision. I wouldn't be saying this if there wasn't merit to it. If it was me, I wouldn't move it. But you asked, and I wanted to give you my experience.
And there you have it.
Best of luck however you proceed.