Thank you!
Broccoli can bolt easily so I make sure it has good water and good light, so it sounds like yours bolted to me.
They can turn so quickly broccoli, if they do bolt and go all leggy you can still eat them but they do not look the same!
Also worth checking you didn't grow tender stem broccoli because that is like the purple one but green
Well, that explains. The package said Broccoli Autumn, but I do grow veg & fruit in pots, and I feel that broccoli has tons of roots. Perhaps needed more water. It did bolt. It also looked as if water was going in and out which could also indicate that the soil was dry, plus I stuck it into the greenhouse 😣. I will give it a go again next year! Thank you for the advice!