Bung: It's another on/off functional switch. If it can't be locked against inadvertent operation it's not an isolating switch. The circuit breaker would be the isolation point.

an isolator switch isn't defined as if it's lockable or not, it's the separation between electrical contacts in it's off position.

Isolators aren't required on GPO sockets 32A or less, a fixed wired bathroom heater does need an isolator as a point of isolation is needed for a fixed wired appliance.

Some circuit breakers don't meet the "isolation" standard as the contact distance in the off position doesn't meet the distance requirements