Get one for face value while you can!
http://www.theguardian.com/business...te-withdrawnI have only had about three of these notes in my entire life. However, about a year ago I was given a lovely crisp unfolded Merlyn Lowther one with the prefix M08 while helping my brother at a sales stand - I changed it for £50 of my own money and saved it. I assumed that M08 was a replacement prefix, but checked and found it wasn't. Still, I decided to keep the note anyway, as I doubt if I could get a better one now from circulation.