It is possible to get vitamin B6 and B-complex containing various vitamin Bs, and also magnesium, etc. so there is no need to get a specific brand. It could help and it certainly won't harm. Just stick to the recommended doses for children. The key is to take the vitamin Bs with the magnesium around the same time. I noticed the boots often doesn't sell magnesium on its own (just menopause supplements), which is annoying. But if you go to a health food shop you can get some on its own.
I don't know why it is in this section, probably because you posted in here lol I am used to you posting in the wrong sections. I just thought it was your anarchist streak. 