Your guide shows programme descriptions in Spanish. Or German. Or French. The channel names are English. The programme information is foreign. Your reseller used EPG sources from another country. You can't read programme descriptions.
A British IPTV reseller whose EPG is in a foreign language used wrong country sources. The channels are UK. The EPG data is from France or Germany. The reseller never localized the EPG language. You see descriptions you can't understand.
The British IPTV services with local EPG have English programme descriptions. The reseller who used foreign sources leaves you guessing what programmes are about.
The IPTV reseller panel includes EPG language selection. The reseller can choose English sources. Choosing foreign languages is a choice. A bad choice that makes EPG unusable.
The IPTV reseller UK operators who serve UK customers use English EPG. The resellers who use foreign languages are repackaging services without localisation.
Here's a scenario that makes EPG useless. You're looking at the guide. You see "Programa de cocina" for a channel. You don't speak Spanish. What is this programme? A cooking show? A documentary? You have no idea. Every programme description is in a language you can't read.
The EPG tells you nothing. The reseller's foreign language data has made programme descriptions inaccessible.
I've tested EPG language across dozens of resellers. UK focused resellers have English EPG. Resellers who repackage foreign services often keep foreign language EPG. The language of your EPG tells you who the reseller is really serving.
An English language British IPTV reseller will have EPG in English. You can test this by reading programme descriptions. If they're in English, language localisation is good. If you see foreign languages, the reseller didn't localise.
The same principle applies to character encoding. Some resellers have EPG with garbled characters because of wrong encoding. The careful reseller uses proper character sets.
A readable British IPTV service will have EPG you can understand. Test by checking several programme descriptions. If they're in English and readable, EPG localisation is good.