Yes, it has a Frost Mode. The Frost Mode is called "Anti-Freeze Mode".
Press the (power) button to switch from Standby Mode to Heating Mode. While in Heating Mode, press the (checkmark) button until the snowflake symbol appears to enter Anti-Freeze Mode.
Anti-Freeze Mode is set to 7°C. This is not adjustable. A zigzag symbol will be displayed while heating and disappear when it is not heating.
https://www.electricradiatorsdirect.co.uk/manuals/reina/Reina-Maia-Manual.pdf