Oh, is that so? It's not really difficult to learn about them, though. You just need to remember those infamous or well-renowned ones and what they contributed to Britain. For example, King Charles I was known for carrying out the Ship Money, which many people in Britain were forced to pay although they were very poor, and that's when the English Civil War began. He got beheaded in the end and Oliver Cromwell took over the country as Lord Protector of the Commonwealth of England
Actually, that's the cross of Saint George the Dragon-Slayer, our patron saint. That cross is the flag of England (not Great Britain - that's England, Scotland, Wales and N.Ireland) and it's ALSO the symbol of the crusaders. Given that one of the most major figures of the Third Crusade, was Richard the Lionheart, the king of England, that's another good association of the cross with the Kingdom of England.