we are subjects here,for the last 2000 years anyhow!
it would seem that a home made catty is ok:
"(6) A slingshot (being a device consisting of an elasticised band secured to the forks of a "Y" shaped frame),other than a home-made slingshot for use by a child in the course of play."
so you are taking one with you to give as a gift to a child!
