We're talking about somebody who arranges flowers in a vase for goodness sake. She's not giving classes to bunches of children, nor surreptitiously slipping a rose into a vase while the choir practice.

CRB checks are only required for any work which is defined as regulated activity relating to children (or vulnerable adults) within the meaning of Part 1 (or 2) of Schedule 4 to the Safeguarding Vulnerable Groups Act 2006. Flower arranging is not such a task, excepting that it (possibly) gives that person the opportunity, in consequence of anything (s)he is permitted or required to do in connection with the activity, to have contact with children. If you read the story, she never had contact with children as part of her job and is quite within her rights to refuse a CRB check.

Maybe we should ban choristers instead.