So I was having a poke around in the privacy settings on my phone toady, came across a tab deep within settings called "Frequent Locations" which by default its enabled. 

This is where things start getting a bit scary, no very scary in fact. In here I discovered my phone has been tracking places I have visited including dates and times I arrived and left these locations, down to the minute. According to it I've visited my home 32 times since installing ios 7.

For anyone wanting have a look or turn it off this is where you can find it. Settings -> Privacy -> Location Services -> System Services -> Frequent Locations

This feature must be making the GCSB's job so much easier.