Cauliflower bolting ?

My cauliflower seem to be growing taller and not really forming a head - are they bolting?   I think I planted them out sometime in March. They are overcrowded a bit 😬 now they have grown so much if the head does grow it will be nearly a foot of the ground - surely that can't be right? I am new to growing them!

They're probably growing tall because you've planted them closer together than they should be. Make sure they're well watered through the dry spells, and fingers crossed they'll still make heads, even if they're on the small-side.