Photos were very helpful! Couple of things, some just FYI:
- Nest boxes don't need to be as dark as people think
- The top on the nest boxes plus the new roost was a good idea, the old roosts are so poorly placed. I would remove the old ones if it's not too difficult, as they're otherwise...
Generalized advice: I'd try blocking nests at night (and then unblocking once they get roosted and settled for the night) for a prolonged period, not just a day or two, but for weeks. Since they're getting closer to POL you should leave them unblocked during the day.
Any photos of your set up...