There are several ways to find out if you have 5G network coverage. The first one is to check with the main UK mobile phone networks who have 5G coverage maps. For more detailed 5G network information there are several websites and mobile phone apps that provide 5G cell tower information and also feature useful tools to help with using directional 5G antennas to ensure you are pointing it at the correct cell tower.
5G Coverage Maps
Vodafone 5G Coverage
Check Vodafone 4G and 5G network coverage with the Vodafone Coverage Map.
EE 5G Coverage
Check EE 4G and 5G network coverage with the EE Coverage Map. Lets you enter your postcode and see coverage.
O2 5G Coverage
Check O2 4G and 5G network coverage with the O2 Coverage Map.
3 Mobile 5G Coverage
Check 3 Mobile 4G and 5G network coverage with the Three Coverage Map.