I have broad beans in greenhouse, though not flowering yet. Have a row outside which were sown at the same time and planted outside at the same time as the ones in the greenhouse.
The green house ones, as you might imagine, are three times as tall as the outside ones. But all are tillering.
If you have no space in greenhouse to put them in the ground, I think I would plant yours outside, which would check them, perhaps with fleece over for a little while to cushion the blow.
I’m no expert, just an idea.