Will simply plugging the cable into the car and the laptop and starting VAG COM mess anything up? The reason I ask is my mate has given me a VAG Com cable which looks like the correct HEX CAM USB cable but if it isnt and is the older one which doesnt support CANBUS could i do damage just by plugging it in?

No.

If it is the wrong cable then it will tell you.

You cannot do any harm by just connecting a cable anyway as you would have to physically change parameters for anything permanent to happen.