Uk ladies help on choosing milk!!

Kim • From UK 🇬🇧 relationship since 2010 🎉🔑🌹👫 want a big family currently 👧👦🏼👶🤰👨‍👩‍👧‍👧
Hey ladies!! I am choosing to breast feed but I'm worried about not being able to and not being able to pick a specific milk!!
I heard cow and gate is thicker than sma, however sma is referred to by every midwife I've seen. 
Anyone have any specific choosing and for what reason?? 
These are just back up plans btw... No judging!!