Q: iPhone 5S displaying "Searching..."

My iPhone 5S isn't connecting to my mobile network (UK) and only displays "Searching..." in the top left corner. Also the Carrier option in Settings has disappeared altogether. Phone was working fine last night, issue only started this morning. I've taken the Sim out and put it into my old Android phone and works perfectly fine, so it seems the phone is the problem not the network.

I've tried the various troubleshooting solutions found on Apple forums and on the internet and none have worked. I don't have an Apple store where I live, the closest is is a 4+ hour journey by car and i'm unwilling to send it away for repairs as I neither want to part with it for such a long time as postage to where I live takes ages and also I don't see why I should pay for something to be repaired when it's a vital part of the product and should be working anyways.

I haven't dropped the phone or put it anywhere it could've been damaged overnight and was turned off for the 7-8 hours I wasn't using it. Anyone know of a solution that isn't already on a forum?