Thank you arduineando for asking that question and JimboZA for answering it so clearly. This is exactly the reason I came to this forum today to find out the reason for this.
In actual fact, I thought it was a mistake in the book and in fear of blowing the LED, I just wired up the resistor before the LED. In my mind it makes sense then that the resistor will reduce the amount of electricity getting to the LED, if you put the resistor after the LED, then in my head, the LED will get a big hit of power, before it get's to the resistor and that will then "slow" down the electricity but the LED should (Again in my understanding of it) have already blown.
Actually using the analogy in the book, if the energy is the rocks falling and the LED is a tree half way down the mountain, then the resistor is a few more trees lower down the mountain, when the rocks start to fall, they will be at full power when the hit the first tree and only will flatten that first tree (The LED), then as the rocks keep falling down the hill, they hit the second set of trees (The resistor) and only then are they slowed down enough to not completely flatten them all. Actually although I can accept what is being said, it still doesn't make any sense.
Anyhow, I've loads of questions as this is all very confusing, but again thank you for asking this question as this is one of the ones that has really got me confused.