Following yesterday's announcement - which news was about a week old - today I've been sent these pictures of the 2nd class business sheet with M12L year code.
The printing date is 19/01/12 and the style of the date and the side of the gaps in the security slits suggests that this might be a printing from Walsall Security Printers rather than De La Rue. This may well be the case if DLR are busy printing different values for the tariff changes, which have yet to be approved.
Update 6 March: Royal Mail have confirmed that this business sheet is printed by Walsall
GERMANT ~ Germany ATM FDC - Germany 2017 ATM FDC, posted on January 3, 2017 from Bonn to Taipei with arrival postmarked on January 19, 2017.