Aura Cannot switch light on

Until recently my Kobo Aura was working fine but now I can no longer turn the backlight on.

In the main menu it states "Light: Off" but this is greyed out such that nothing happens when I press it.

I thought it may have been because my battery was low at around 20% so I charged it up to 40% with no luck.

Resetting was also no help.

Has anyone seen this or can anyone suggest what I can do to fix this? I assume if I do a factory reset I'll losse all the books I have side-loaded?

Thanks!