The new multiplayer God of War game, Ascension, will be released in the UK on 15th March 2013.
We didn't know the 14th March Australian and New Zealand date, nor the 13th March rest of Europe and PAL regions date.
All the Collector's Edition contents are the same as in the US box, including that DLC pass that "unlocks all future DLC for the game at no additional cost". We're going to hear more about this soon, apparently.
The Special Edition has all the content of the Collector's Edition box minus the figurine and DLC pass.