2nd class blue Machin security stamp counter sheet 2016 version M15L
The 2nd class counter sheet was reprinted on 04/07/16 and appeared in October. Sheets printed in February have also been reported, as well as the later reprints in October & November.
SG U2957 (also used for earlier years).
Cylinder blocks of 6
Date block of 8 - 04/07/16 or 28/10/16