Replacement battery for 47508 Travelmate travel alarm clock

Where does one replace the batteries for the 47508, and what battery type is it?

On the bottom / back of the clock there is a small plastic cover (with an arrow). This is the battery door. Inside you will find a button cell/watch battery that needs to be replaced with battery size ‘LR44’.

47508-battery-door
47508 open door instructions