Blue tit on eggs in box

Hi

I have a beautiful blue tit nesting in a bird box. 
The box gets sun from mid morning to around 2pm. Should I add extra shade to the wall above the box without disturbing the box?

I also had a peep into the box with an endoscopic camera to see how things are progressing. She was sat on her eggs and I’m sure she saw the camera ( slim endoscope type).Now I’m worried she might leave.

Any advice would be greatly appreciated.