I've switched my phone from Sky to Tesco solely because of Sky's new roaming cost. I assumed that as they both use O2 that the service would be the same but I'm noticing really patchy internet in places where it wasnt previously a problem. I contacted Tesco helpline and they suggested that I changed settings from 3G/LTE ( auto) to 3G only, which solves the problem but doesnt give me 4G when available. Is anyone else having this problem?