Ok, sorry if I begin to rant, but NO school is advised to have a 'no touch' policy.
As a teacher, you have a duty of care to keep children safe, and act in loco parentis
Legally, a teacher can intervene physically if:
A child is injuring others
A child is injuring themselves
A child is damaging property
A child is behaving in a way that is likely to disrupt good order.
Any physical intervention taken must be reasonable, proportionate and necessary.
Sometimes touch can be a calming influence, but this must be professionally judged on each individual's history by the teacher.
IMO, the legal guidelines should be clearer- for example, 'damage to property' could be breaking a pencil in two; hopefully no teacher worth their salt would restrain a child for that!