I wasn't happy buying a 7500T because it seems the stocks are low in Australian shops, and the remaining units are being discounted. However, I have now bought a 7510T after discovering it is more-or-less the same unit, just with some minor cosmetic differences.
Not surprisingly, the 7510T auto-tuned the local multiplexes because it's tuning parameters for Australia tell it to use 7 mHz spacing in both the VHF and UHF wavebands. It has a secret maintenance menu that allowed me to copy channel.db, setup.db (empty) and rsv.db (one trivial record) to a usb stick. (I haven't had time to examine the channels yet).
"As usual", it arrived with back-level (1.08.22) firmware, so I usb-upgraded it to the latest from the humax web site (1.08.26). The first usb stick was ignored, even though it was empty except for the upgrade package, probably because it is usb3. My next stick was usb2 and was read, but there is a bug in the upgrade procedure. After the firmware upgrade is successfully installed, the humax reboots and immediately starts reinstalling the firmware!! It doesn't detect that the package on the stick is at the same level as the running system. After the 3rd "upgrade", I used the back-panel power switch to kill the loop during the "downloading" phase. I removed the stick, powered the humax up and was relieved to see it working normally under the new firmware.
The 7510T has a different remote control, which gave no end of fun with both the FOX-T2 and it on the same shelf! I found the tip to change the remote control frequency on this forum, but managed to misunderstand the instructions and put my T2 onto frequency zero so it lost the connection. Luckily, I could reset it to default frequency 1 and the T2 was waiting to talk to it again... then a change to channel 2 for both the remote and the humax was successful.