ew002lcdg-2 eurosec alarm can't set low batt fuse

[Flisso]

Hi all,
We had a momentary power outage on sunday at 9am and my alarm started going off inside the house. The key pad says "can't set, low batt", I opened it up and can't see a battery, it seems to be connected to the mains. I am really not good with DIY and I've looked online where I've learned it might be a fuse that blew and not the battery. Can anyone tell me where this fuse is? Is it in the alarm box (I have 2 inside my house) or the key pad, where do I look?
Please keep advice simple, I am a simple person. Thank you so much for taking the time to read this.

 

[T1GERIII]

Post picture of the main panel inside the house

 

[sparkymarka]

Did you open the keypad or main box ? Main box is about A4 size

 

[Handymanjo]

Control panel is the larger box