Faisal Jan

Hi, I’m UK tax paying resident, Belgian and Afghan national. I got some cash as gift from friends and family members. I want to bring it with me to UK and put it in my UK bank account. Could you tell me if I need any proof for UK customs at the airport? And the national language of Afghanistan is not English, so will it be acceptable in any other language? Kindly give me all the informations I need to have before I come back to UK. Thanks in advance for your help.