Hi Simon

The last one we did you removed the glove box then the fan and work along the ducting with your hand and you will feel the resistor, twist quater of a turn and remove from inside the duct,you may need a new fan loom as they are common for burning the multi plug of the resistor out.These are a bit of a pain but not as bad as dash out.From memory about 1-1.5 hours ish should cover it
Regards John