So, in chronological order of issue, rather than discovery, linked to the original post (where the pictures are):
26 January - retail book 6 x 1st with change to postcode advertisement - MSIL (discovered April)
24 February - retail books 12 x 2nd, 12 x 1st. MTIL (discovered April). Both were sold by Royal Mail at Stampex but not noticed at that time. The 1st class has no printer's name and was scheduled for issue on 15 December 2009 although we believe that the first Bureau distribution was actually in January. One printing of these stamps does not have the MA10 code, and these are still being issued by Royal Mail's Tallents House Bureau against stock code UB309. As Royal Mail have not separately listed the booklets or stamps with MA10 security code, the old stock for this code will probably be replaced by MA10 coded stock with no prior announcement.
25 February - Olympic/Paralympic mixed retail book 6 x 1st - MCIL (discovered April).
30 March - retail book of 6 x 1st with London 2010 advertisement MSIL (discovered April) - this was the first booklet in which the new code was noticed, which prompted dealers and collectors to look back at the year's earlier booklets.
8 May - at the London 2010 Festival of Stamps: retail books of 4 x 1st Large and 4 x 2nd Large, code MFIL. Previous versions had the source code in the word FOYAL.
8 May - in the King George V prestige stamp booklet 2nd class, 1st class & 50p coded MPIL. This was the first 50p stamp issued other than in counter sheets. What sets these three apart is the existence of two different types of security slits (paperclip) and differences in the interrupted perforations.
13 May - 2nd & 1st class coils of 500 and 1000 coded MRIL. The first security stamps on ordinary gummed paper and therefore without security slits.
24 May - 1st class counter sheets - code MAIL. Printing date 10/03/10
10 June - 1st class Large Business Sheet - code MBIL instead of ROYBL, printing date 09/03/10
30 June - 2nd class counter sheets - code MAIL. Printing date 10/03/10 as 1st class.
30 June - 1st class Business Sheet
12 August - 2nd class (letter) Business Sheets - printing date of 05/03/10.
November - the 1st class Large from counter sheets (code MAIL) - we have limited supplies. Picture now here!