Sounds like those weren't appropriate measures if someone can get round them so easily.
When I had a shotgun license, my shotgun was in a locked gun cabinet inside a locked room. The cartridges were in a separate locked case out of sight in another room, and I had the only keys for all 3 locks, all of which were on my keychain which was on my person at all times.
When I didn't have them on me, they'd be in the hidden space behind the hinged piece of skirting board behind my bed.