What would I have to do once I have a Bangladeshi driving licence, when I enter the UK?

a foreign driving license is only valid in th e uk whilst you are over here on holiday, you need a full british license if you want to keep driving here. my mate had to take a british driving test when he moved here from egypt even thougth he held his for twenty years he still had to take the british one, i think jhe had a couple of years using his original liecense but then it became invalid after two years as a resident and he had to then sit the test, but check out the dvla site