Machin M11L Security Machin - 1st class mixed content booklet

As promised, and thanks to Richard's skills with his scanner, we can now show the first 2011 Machin security code. 

The Thunderbirds mixed booklet has M11L at top left, and MCIL at top right.  Like all booklets of 6 these should see early and widespread use and should be found on mail and in kiloware by the end of January.