I get really bad connection in central London locations, such as Oxford Street, Covent Garden, Liverpool Street, many City of London areas, Mayfair, Baker Street and many more.
I have an iPhone 13. 5G auto is on. I have tried my friends EE sim in those same locations in my phone to test, and the EE works perfectly in every location. The ID consistently (over the past 2 months I’ve had it) absolutely never works in these areas. This is despite often having full bars of 4g or 5g in these areas, but get absolutely zero internet connection when trying to load a website. I have also tried my iD sim in my second phone (S22 5g) and get the exact same results.