I got my phone as part of an upgrade (wish I'd kept my iPhone 5) at the end of March 2015.
I live in South Hampshire UK.
Been having the random 'no service' since then and have got Vodafone UK to change my handset twice ðŸ˜
When it kept happening I then asked for, received and fitted a new SIM card.
I have also requested info from Vodafone 'Tech Support' (what a joke they are!) re the LTE settings and have received no info 😕
I have tried Big Al's settings and it is happening less frequently (used to be at least three times a day now it is only once or twice a day).
On numerous occasions that it has happened, i have compared my wife's IPhone 5 and it has a full 3G Signal.
I hope you have better luck that I have with this.
I am now considering asking for another new SIM card from Vodafone.
Maybe if everyone experiencing this issue asked Vodafone for a new SIM Card every month or so then soon they would have to realise that something is not configured properly with their network and perhaps they might eventually get round to doing something about it. 😮
If this is not resolved by the time my contract expires then I will most definitely be moving to another service provider.😟