Bees nesting in bird box

I wonder if anyone can give me some advice.

I have a webcam on a bird box on the side of our house.  Last year we had blue tits nesting in it and five chicks fledged successfully.  Initially the blue tit had a problem with evicting a resident bee!

This year, although the blue tits were initially prospecting the box, we have had no interest.  I switched on the camera last night to see if there had been any activity to discover the box seemed full of moss.  After watching it for some time, it seems that it is now occupied with quite a few bees.  I managed to count five, but given the movement of the moss, there is a great deal more in there.

I am not too worried about them being there, as I am aware of the decline of bees.  However, do we leave them alone?  Will there be an increase in bees?  I have also read that if I contact a local beekeeper they may take them away.  However, I wouldn't want them taking the whole nestbox away as there is a camera in there!

Any advice will be gratefully appreciated.

Angela