Charles Darwin the 500 pound giant tortoise?
No! He isn't that. He discovered evolution.
If you mean from predecimal to decimal notes, there was no change since the name and the value remained the same. If you mean the current Bank of England Ten Pound note featuring Charles Darwin, it was first issued in 2000. It replaced the Charles Dickens Ten Pound note which was last issued in October 2000 and ceased to be legal tender in July 2003.
You cannot date most British banknotes from just the serial number. You need a combination of the Chief Cashiers name, the serial number and the denomination, and sometimes the design of the banknote. For example - A Bank of England Ten Pound note, Chief Cashier Merlyn Lowther, serial number KL01 123456. This information alone tells me that you are referring to a Bank of England E Series Ten Pound note featuring Charles Dickens on the…