if the fan is ceiling mounted ,some electrical wholesalers sell a fan isolator pull switch. if your fan is directly above bath ,i recommend rewiring fan supply by repositioning pull switch over by the door. if the switch is wall mounted then pull the supply cable out , re-route to ceiling and fit an ordinary 5amp pull switch then wire back down to fan! if its a timer fan it gets a bit more complex . pull switch better with a neon so you know what position pull sw is in.....
david soutar, January 2009