The headphones that I've narrowed it down to from what I've read about are the AKG 2K40 MKII and the AKG K271 MKII. There is a fairly big price difference between the two but I realise that they should last me a very long time although I would still rather spend less than £150.
I'm buying headphones strictly for listening purposes and I will be using them at home 99% of the time. I wont be doing any recording and a majority of my listening is though an mp3 player (I play flac on it) and I also don't have a amp. The genres that I listen to the most are metal and rock with bands such as: Porcupine Tree, Opeth, Wintersun, Black Sabbath, Atheist, Blind Guardian, Dream Theater. If you have any other recommendations then feel free to say. Thanks for any help