The rubber mallet trick worked fine for me.
A recommendation is to put some cardboard across the fins of your radiator, just in case you swing and miss.......
Fan clutch is free spinning, but a gentle knock on the spanner/wrench/socket arm with a rubber mallett should be enough to free it up.
It's a given that you'll need 2 litres of BMW genuine coolant when you refill. Not cheap but certainly worth it.
Also, there are at least two temperture rated thermostats. When I first replaced my thermostat BMW gave me a 90 degree (celcius) thermostat which made the car run hot. Took it back and got an 80 degree one.
Cheers,
Trevor (Sydney)
E46
00' 323iA (70,000 kms)