Moon Rigel Max battery Q

Does anyone have any experience of a failing battery on a Moon Rigel Max front light?

From what i thought was a full charge, the light gave up after around ten mins with the leds in the switch flashing an odd array of lights, seems to indicate a battery fault.

the light works when connected to charge, the leds indicate its charging, but it doesnt.

I cant even see how the light might come apart? its only a couple of years old, but this feels like its now disposable?