Complex sentence: In May 2010, Revelation Films announced plans to release the series on DVD, with only the first 3 series have been made available by Revelation, as of winter 2012, there hasn't been any further DVD releases at present.
Split into simpler sentences: In May 2010, Revelation Films announced plans to release the series on DVD. So far only the first 3 series have been made available by Revelation, as of winter 2012, there hasen't been any further DVD releases at present.