1st class Large gold Machin security stamp from retail booklet of 4, 2011, coded MA11 MFIL
The retail booklets of 4 stamps were reissued on 22 March 2011 without the printer's name on the back cover.
This is the 1st Large Letter NVI stamp printed by Walsall Security Print in booklets. The year code MA11 is now just above the letters 'ge', the source code on these booklets of 4 is still MFIL and has been moved to the lower right 'paperclip'.
SG U2972 (also used for later years)