Blue tits scared off by robins

I have a nestbox which has been occupied by bluetits every year. However, this year I had to move it to the opposite side of the garden as the post it was on was damaged.

the bluetits found it and started building their nest in there. However, recently there have been two robins in my garden constantly and when they fly away they go into the tree behind the nestbox. I assume they have a nest in the trees.

i haven’t seen the bluetits for about a week now so I’m worried that the robins have scared them off. I know robins are territorial and maybe the nestbox is too close to the trees.

my question is, can I do anything e.g. move the box, or do I need to just leave it til after summer and hope the bluetits come back? I know they have built the nest in the nestbox but there doesn’t seem to be any sign of them coming and going anymore.