Every month I notice that iOS' 'System Services' uses a large amount of my limited mobile data. The phone spends most of its time connected to a Wifi signal and I therefore don't think its unreasonable to want to reserve mobile data for truly mobile tasks (when I'm not on a Wifi signal). I have resorted to turning off my mobile data all together and then only turning it on when I want to use a service like maps. This is an extreme and unsatisfactory approach and even with this approach when I have mobile data active for several hours (for example whilst travelling so that I can use a map application) then iOS still seems to use the mobile data for large downloads.
These should not be system software updates because I have turned them off:
But there are other software updates (maybe still system software updates?) that make up most of the data used:
I was going to try turning off the App Store's mobile data access but this only shows as 3.6 Mb and not the 352 Mb of Software Updates under the System Services page. Is there a way to configure / use iOS to make sure it uses Wifi for its software updates and does not squander mobile data on these software updates that could easily wait an hour or two until I'm back on Wifi?