GL-X750v2 version update confusion

Did you resolve this problem? I have also just purchased the GL X750v2c6 in the UK.
Current Version 3.104-3.217
Compile Time 2023-05-08 10:37:25
Last Update 3.104-unavailable
I have checked for updates, and on the download page it has several updates for the X750 but nothing for the x750v2.
Having downloaded the latest for the X750 I get this message:
Firmware Verification
The uploaded firmware is older than the current firmware or is a 3rd-party firmware.
t make break the router due to hardware incompatibility.
You are also suggested to NOT keep settings.
Version Unknown
Downloaded version: openwrt-x750-4.3.7-1222-1703233128.bin.

Very confused .
How do I get rid of the downloaded file in case it tries to upgrade?
Where has it loaded and saved to?
Samba can’t be loaded , not enough space?