What is the best teaching assistant qualification to aim for?

No, I am not left-handed but I do have two left feet!
Your DD could do some investigations in the meantime.

I learnt, to my cost, many years ago when I embarked on a career in pre-school education that such jobs are deemed high in job satisfaction and are therefore often low paid. You pay dearly for enjoying the work and for being able to be a more 'hands-on' Mum. Luckily I could afford to make such a choice but often had to bite my tongue when graduate qualified professionals queried our pay.

If the DD concerned is a graduate she may well be able to get on a retraining scheme that would get her into teaching - where the earning potential is (theoretically) higher.

My d has a degree in early years education. She is the manager of a preschool. Now she is a single parent and her pay is so low she gets benefits and we help out financially. She is dedicated to her job and the disadvantaged children many referred by SS. At a child protection meeting one day she referred to the fact that the cleaners at County Hall earn more than she does. The SW was shocked but she loves her job and will stick to it.

annsixty - she sounds wonderful, thankfully there are those who do continue despite the poor rewards.

Because of the holiday issue, schools are usually inundated with applications for any TA role. Most will only interview those with relevant qualifications and / or relevant experience. These can usually be done through a local college but any distance training needs to be undertaken in collaboration with school experience.

Roll on basic income.
Nobody should be expected to manage a preschool and still be on benefits because the job is not deemed worth a decent wage.

My D would be very pleased to hear your comments. She is 51, twice the age of most of her staff but I think that is what makes her take the responsibility of her position so seriously.
The man who owns the school admits his staff are responsible for making money for him, but he is under no obligation to pay them over the going rate.