Even as this was in draft, news came in of even more new Machin definitive stamps or variants on last year's stamps. So first a summary of what we have had so far this year.
Following a suggestion from MachinManiac Larry, I have changed my terminology. PBP now refers to PLAIN backing paper and SBP to SECURITY backing paper.
2015 Year Codes (stamps in [ ] brackets not yet in stock)
2931R.5 - 2nd class coil - MRIL - reported used, then mint
2911B.5a - 2nd class business sheet MBIL on security security backing paper (SBP)
[2931.5a] - 2nd class book of 12 MTIL on SBP
[2936.5a] - 1st class red book of 12 MTIL on SBP
[2914B.5a] - 1st class red business sheet MBIL on SBP (no picture yet)
3745a - 1st class amethyst purple book of 6 on SBP [O15R]
[2937.5a] - 1st Large book of 4 on SBP (no picture yet)
2016 Year Codes (M16L unless otherwise stated)
2913.6 - 2nd Large counter sheet printed 15/01/16 - plain backing paper (PBP) (see below)
3002.6 - 2p counter sheet printed 12/01/16 - PBP (see below)
3010.6 - 10p counter sheet printed 11/01/16 - PBP (see below)
3133.6 - £1.33 counter sheet 08/01/16 - PBP
3744.6 - 1st class amethyst counter sheet printed 21/01/16 - PBP [O16R] (see below)
We have stocks of some of these, in some cases very small stocks and only singles; we hope for sheets to arrive soon which will allow us to break out cylinder and date blocks. Some booklets we have no cylinders but hope for them to arrive soon.
Last year I reported 5 new stamps (plus the Alice in Wonderland booklet) by 7 March. This year we have 5 stamps with 2016 year codes, plus 7 more printed backing paper variants with last year codes. Fortunately there are none scheduled for release at Stamps, but who knows what we may find on the Royal Mail stand that haven't already been found in Post Office branches and supermarkets ! ?