I'm going to answer my own question, is the AKG K702 a better option compared to the Philips Fidelio X2hr in terms of sound quality, sound stage and instrument separation, in a word, yes.
AKG K702 = a proper open back, sounds absolutely amazing straight out the box, perhaps a shade lacking in volume level due to the 200mW drivers, the sub bass interferes with the vocals, backing the volume off a little solves that. For the price I'm well happy for the sound quality I'm getting.