Thanks for that info Nancy
even what we think is secure cheeky little hams will have a go at escape. Yeah they are pretty small ties, I think they are 3mm or something like that maybe but are strong enough. I'm realizing I would need to drill a small hole though as the drill bit I intended to use is bigger and then there would be a gap between the cable tie and the hole and little teeth could be tempted to chew that bigger.