The BT modules do allow you to change the date format but so will the updated 5610 (GW-M5610U-1ER, U for Updated I guess), though you have to accept the LED backlight along with it.
If you’re not into the red graphic on the 5610 you could try and track down a G-5600E-1:
Which is being phased out (and replaced with the LED backlight + date format option version), and was not available in the UK AFAICT, but it has a normal LCD, the EL backlight and solar charging but not the radio sync of the 5610.
The BT modules do allow you to change the date format but so will the updated 5610 (GW-M5610U-1ER, U for Updated I guess), though you have to accept the LED backlight along with it.
If you’re not into the red graphic on the 5610 you could try and track down a G-5600E-1:
https://www.casio-intl.com/asia/en/wat/watch_detail/G-5600E-1/
Which is being phased out (and replaced with the LED backlight + date format option version), and was not available in the UK AFAICT, but it has a normal LCD, the EL backlight and solar charging but not the radio sync of the 5610.
The number of variations is dizzying tbh.