Maybe it’s time to switch to a service provider, which has got a better network services in the locations you’re using your mobile, @scott1uk. 

It wasn’t just in the same location I drove a 100 mile today and it happened in over 6 calls I made 

Are you in the Midlands area shown below, @scott1uk? 

Hi @scott1uk 

Sorry to hear this, please could you try the following and let us know how you get on;

For iPhone;

Settings > General > Transfer or Reset eDevice] > Reset > Reset Network Settings.

For most Android;

Settings > System > Reset options > Reset Wi-Fi, mobile & Bluetooth

For Samsung; 

Settings > General management > Reset > Reset mobile network settings

Resetting network settings will NOT reset any personal data (Photos, Videos, Contacts etc) only network settings.

Tom