Here in UK you can't sell anything like that unless it has been CE tested and has a label to prove it. It is possible to do it yourself, but such a palaver. At least one brand of thread has a CE certificate which makes the job slightly easier.
I can't see it changing when we leave the EU.
"The CE marking is required for many products. It:
shows that the manufacturer has checked that these products meet EU safety, health or environmental requirements
is an indicator of a product’s compliance with EU legislation
allows the free movement of products within the European market
By placing the CE marking on a product a manufacturer is declaring, on his sole responsibility, conformity with all of the legal requirements to achieve CE marking. The manufacturer is thus ensuring validity for that product to be sold throughout the EEA. This also applies to products made in third countries which are sold in the EEA and Turkey."
This testing is also very expensive as I understand too and is way out of reach for majority of crafters just wanting to cover the costs of their hobby.
I know this applies here in the USA. I am not sure what the requirements are for donated items. I think the rules also apply -- but I haven't checked into it. Once the rule/law was passed, I stepped away from children's anything.