Aidensmama - you say "It is also really important to stay well hydrated and fed"
No it isn't Breastfeeding happens just fine, whatever the mother's hydration levels and diet.
"have a constant supply of water or squash next to you"
Not necessary - though mothers may feel thirsty in the middle of a feed, so this might be useful from a comfort POV.
"and eat plenty of protein"
Not needed - protein levels don't have anything to do with bf.
" and don't be messing with low fat foods just don't go over the top with full fat stuff."
She can eat what she wants (she might want to take a long term view of her own health and reduce full fat foods, of course).
"Try not to stress as this will affect your hormone levels which may hind milk supply and let down"
No it won't....breastfeeding is pretty robust and unaffected by stress. Acute anxiety or fear may inhibit let down.
Sorry to pick this apart, but often people who have had some care/medical/health/nurse based training hear these myths, and it gets passed on. It's ultimately undermining to bf, IMO, as people think if they are stressed, have a crappy diet, don't drink loads of fluids, then they cannot breastfeed (or even shouldn't breastfeed). And the good news is it ain't true