After turning on the pedometer and having a 5 minute blast on Angry Birds I'm back to 22,400 wakeups and 0.8% time in C4 sleep mode.

Turning off the pedometer without a reboot inbetween returns the wakeups down to 852, with 82.8% time spent in C4 sleep for the CPU.

Therefore, the unusual number of wakeups is down to the pedometer. I'll leave it off for a while and see what happens to the battery life.

Thanks for the info on the 50% CPU use when charging vi_, nice one