Robins nest in my shed

Hi everyone.

I need some advice.I have a Robins nest with 4 eggs in it just inside my allotment shed door.

The mother is sitting on the nest and gets out at the last moment I enter even though  I am noisy every time through a gap in the roof.

I want to carry on using my shed but don't want to cause her to go and the eggs be abandoned. 

Please advise me here......I feel very lucky to have this wonderful little family in my barn with nature at my allotment. 

Steve