What Do You Mean My Money is Worthless?

I was reading YAHOO UK today and almost had a heart attack!  According to the Telegraph today June 30 was the last day to trade in your old 20 pound note, the ones with the picture of composer Edward Elgar on them, that after today the stores would  no longer  accept them.  Nor would  banks have to exchange them for new notes.  That from now on the only 20 pound notes that would be accepted were those bearing the likeness of Scotish economist Adam Smith.  The only place you could  exchange the old notes  after today would be  at the Bank of England.
When did this happen, when was this decided, why didn't I know sooner?   Though I'm an American I read the British papers online every day and up until today I'd never read about this.  I yelled at my computer, cursed the British banking system and threw a fit.  How in the world could I exchange bank notes at the Bank of England when I'm sitting in the USA?
Why would I panic like this you say, why would I be worried about old British 20 pound notes, well let me tell you.  Later this year we're going to England on vacation and while the pound was down against the dollar we decided to buy a bunch up because the last time we were there is was $2.04 to buy a pound and this spring it was $1.45, a big difference.  So we bought our pounds through our bank and put them in our safety deposit box, never occurred to us to see whose picture was on them.  It's usually some middle-aged lady wearing a crown.

But  after reading the article we stopped by the bank, opened our box and to our great pleasure we found Adam Smith on our bank notes, we were very happy.   Though his name  doesn't sound Scotish we were glad to silhouette on the backside .