Alternator nut size, turning motor over

Can someone tell me what size the nut on the alternator is? Carbon cleaning and I need to crank motor over. I haven’t removed any of the front end so as I’m sure you all know there isn’t much room to work with, having a mare.
Open to suggestions on this.

def remove the front core support.

The alternator nut is a 24mm.

Created this from an old socket