Nest box removal

Question
Just a general question I couldn't find anywhere on the net sorry. I am breeding a pair of budgies for the first time, no luck so far. I remove their nesting box from the outside of their cage whilst I tend to their water, food etc as its the only entry to the cage possible. I was just wondering if this is puttin them off? Because I remove the box then put it back.

Also, the pirch on the box is plastic, the box its self wooden though, is this creating a problem?

Answer
I do not answer questions on parakeets, since I am not an expert on them, but it seems they are not laying eggs in the box only because they don't find it safe. Parakeets can be very timid, if they lay their eggs in something that is being removed and put back, they probably do not find it a good spot to raise a family. Just a guess.