I came across this today. Without me searching through the regs, could anyone confirm if this is still current, or indeed true? It mentions mains voltage fans being allowed in Zone 1 providing they are protected by the correct RCD and IPX4.
http://www.diydata.com/electrics/bathroom_electrics/bathroom_electrics.htm
http://www.diydata.com/electrics/bathroom_electrics/bathroom_electrics.htm
Zone 1
Requires electrical products to be IPX4 or better, or SELV with the transformer located in zone 3 or beyond. If the fitting is 240v, a 30mA RCD must be used to protect the circuit.