Can i just say something about the 'just school mums' and recruitment.
First, women dont appear fully formed at the school gate. Before becoming a school mum, they may have done all sorts relevant to the role. School mums we have employed have included nurses, rugby coaches, architects, engineers, childminders, social workers, care assistants.
obviously its a low paid job and entry criteria vary from post to post. This means sometimes noone with the qualifications and experience applies.
During the interview process you observe interaction with children. Very often the task is to read a story and do some learning.
You pick the person with the best soft skills in that task and best potential to learn the job quickly.
You arent anticipating they are a fully formed TA. You are expecting them to be a bit useless for a while, then by the end of the year pretty good after they have had lots of support and some courses. More like an apprentice. Its not that the job only needs a 'school mum' its thats all you have to pick from so you train them up.
(Obviously some schools are rubbish and dont support/train but that hasnot been my experience luckily.)