Agree with what’s been said about checking signal. All of the internet providers have maps which show coverage. Or go to the various shops and give them the postcode, they will check signal.
I’ve got T Mobile on a contract you get a usb cable and a sim card in a stick. I live on a farm in an area where none of the providers guarantee good signal, so some days I only have GPRS and others I have 3.5G. I can watch vids on youtube etc, it’s not fast enough here for the watch-again tv sites, although it was ok at Hertford (why it’s so important to check coverage).
Today, for example, it’s windy and cloudy and the signal is rubbish.