How can you import and sell cheap chinese bathroom fans in the UK, when they have no safety or agency approvals? OP, ensure your product is legit.
Yet we're worried about fusing and the ET Wiring Regulations. Like a fox in the henhouse.
The Big Clive fan, wasting 1.2W all the time- looking at the cooked 22k resistor, phenolic pcb, unknown plastic housing (UL 94V??) it's your usual POS.
I've seen other fans with electronics such as MCU and PIR sensor, use instead a capacitive dropper.
The only safety component is the dropping resistor, hopefully they are infallible. Not so with thick-film TO-220 resistors for some reason, I've seen them go lower in value with abuse.
This looks like metal-oxide running hot 24/7 just to power a CMOS timer
