Connection dropped even though Network service is good (incl. messages, calls, 3G & 4G data)

Hi there,

I have an iPhone 5 (64GB) with iOS 8.1.2 (problem occurred in 8.1 also). Couple months ago, I couldn't send and receive txt/messages, calls or data even though my Network Service was good. I discovered that if I reset all network connection settings that my phone would work correctly again - and it did for a couple of months. But for the past week, my phone has been 'disconnecting' again - like 15 to 20 times per day. It's as if it's switched to Airplane mode even though I'm still totally connected to the network - I can see the vodafone service bars showing I have good service - 4 out of 5 circles etc. Interestingly that while this is happening, if I'm near a WiFi network, all my data connections through Wifi work perfectly - no trouble with the Wifi - my phone is at least as good as an iPod Touch! ;-)

So far I have done the following in an attempt to rectify it:

I restarted my phone - didn't fix it.

I reset my phone by holding the home and on/off button until it restarted - didn't fix it

I reset all network connections in my settings (again) - didn't fix it

I deleted my entire phone and restored my backup from 1st December - didn't fix it

I upgraded from iOS 8.1 to 8.1.1, then to 8.1.2 - didn't fix it

I took my SIM card out and used my wife's SIM and MY phone still had the problem - my SIM worked fine in her iPhone 5s (yeah, she's got the better of the two phones - doh!)

Each time the phone worked properly for about 5 to 10 minutes initially and then it went 'offline' again.

I've also tried switching Airplane mode On and then Off just to see if it would trigger it re-connect - didn't fix it.

What I have found is that if I toggle Mobile Date off and on, and Enable 4G off and on, it sometimes kicks the phone back into action.

Unfortunately I'm 1 or 2 weeks past my warranty (typical!) so I'm hoping someone here might know the answer or Apple might take pitty on my bad luck and give me a hand...

Thanks in advance for any help 🙂

Jonno