No Service on iPhone 5 after flying from UK to Switzerland

Hi

I have an iPhone 5 which I've just travelled with from the UK to Swtizerland with - it was working perfectly on the plane, then when I landed I got "No Service" - my sister is with me with an iPhone 4 on the same network and she immediately got signal, so I felt it was odd...

I restarted, with no luck, then reset and no luck, and took my sim out / cleaned it etc, no luck, I have then restored it, and the signal still didn't come up...

I have tried airplane off, on, shut off, on, then tried manually selecting the network, no luck...

Any ideas? My iPhone hasn't been droped or anything and there should be no reason for it to have suddenly stopped working after 1hr flight.

Please help!!!