No, if there was no local isolator you turn it off at the CU, disconnect the fan, switch CU back on, brush teeth. Simples!
Is the average home owner going to have the required step ladder, a voltage indicator, set of screwdrivers, strip connectors and the knowledge to safely disconnect the fan in the dark?
I certainly wouldn’t want my almost blind 74 year old mother attempting this when alternatively she could just turn a switch off.