*Blue Exorcist DE Part 2 is also £17.99 @Base.com (these are brand new, not used copies by the way).
Blue Exorcist Definitive Edition is a release of the anime that now includes English dubbed as well as English subtitles and in high definition, The 1st part of the anime has more canon material relative to the manga (which is great by the way) so seeing it animated in high definition was a treat and at a good price, the dub is ok I suppose. I have bought both part 1 and 2 myself and they are just blu-ray (no combo pack)
Also bare in mind that The DVD releases have NO English dub just English subtitles for japan dub for those who are not interested in the dub or high definition DVD releases are
Part 1 - £10.99 @ Base.com
Part 2 - £11.99@ Base.com