fallen bird box

Hi,

I have a Robin box on my wall behind a large Holly bush, I hung it there about 6 years ago and it was left forgotten, now it is very well weathered. 

I was so excited to see that this year a pair of Robin's have been busy building a nest over the past week. 

I woke up this morning to find that the box had fallen from the wall, the roof had broken off as the nail had come out of the mortar. 

One of the Robin's was still in my garden flitting around, so I did my best to tape it back together and hang it in the same place on a new nail.

The nest inside was still there and looked intact so I don't think it had been attacked or tampered with. 

My question is do you think the Robins will return to it?

They were still in the garden this morning when I hung it back up around 0630hrs but we haven't seen them flitting in at all today. 

If anyone could give me some advice it would be greatly appreciated as I am quite disheartened by the ordeal...