I use a large piece of 4"x2" as a drift on the spanner ,then wack wood with club hammer-allows you to do it away from bonnet thats on my 300tdi-not needed to do the td5 yet,but will try same method (except other way of course).
Took my fan off about 5 years ago to do something and never bothered putting it back on again. Never overheats and stops mud and other sh*t being sprayed around the engine. May improve MPG but debatable.