Ok i've got a Nexus 4 with location history enabled (which is viewable at maps.google.co.uk/locationhistory) and works well.
I've not added a Nexus 7 and this is now fighting with my Nexus 4 to report where it thinks I am (Nexus 7 usually stays at home).

If i turn off location history on the Nexus 7 then it also turns it off on the Nexus 4.

So how do i solve this problem so that the Nexus 7 stops reporting its location to google?