Series 6 is being split in two. Half of the episodes in spring, the other half in autumn, with a big plot twist/cliffhanger in the middle.
Actually, I'm kind of alright with this. Sure I'd like it all in one go, but this way means there won't be a six month wait until Christmas. Swings and roundabouts. I'll live. I'm sure they know what they're doing and it'll be interesting to see what they've got planned.