IOS 8 High Cellular Data Usage

Upgraded my wife's iPhone 5 32GB to IOS 8 yesterday. About an hour after I upgraded she got an SMS from her provider saying she only had 100MB left of her data package. About a minute later she got another SMS to say it ran out. I reset Cellular Usage Statistics and bought another 250MB data bundle.

About 2 hours later she got another SMS saying she had again used up all data and that out of bundle rates apply, when I checked Data Usage it had used 297MB. She did not use the phone at all during this time.

I have disabled everything under Use Cellular Data For: long ago, except Contacts, Find iPhone, Maps, IMDB, Mail, Settings, Weather and WhatsApp.

None of these Apps had excessive usage under them, some a few KB. System Services had used 404KB.

Personal Hotspot was Off.

Everything in iCloud except for Find My iPhone is off. iCloud is signed in.

Use Cellular Data is off under iTunes & App Store

I have gone through all the Apps at the bottom of Settings and none of them have Cellular Data active.

iTunes Radio under Music is not set to use Cellular.

Is there anywhere else I can check what would be using so much data, have turned Cellular Data off for now?

I am at a loss, I upgraded my iPhone 5 16GB the same way as my wife's and I have not used any extra data, sitting at 247MB since September 1st.

My wife's phone has not changed since before the upgrade, so all settings were the same and it has never used this much data.

Any help would be appreciated.