Update 5 December: BPMA have advised that they are selling the blank BPMA envelopes for 50p, and
"If people hand their covers to the Search Room staff by mid afternoon they can get our special handstamp."
Camden Machins and Robins with new ADGB12 code, signifying
A - self-service
D - December
GB - Great Britain
12 - 2012
BPMA's version with same coding but overprinted 'The B.P.M.A.'
It seems that these are the machines last used at Perth, and the session numbers have not been reset to zero. If I recall correctly they weren't zero when they arrived at Perth either.
Click on the images to see much larger ones.
At the end of the year the BPMA code will change to
UPDATE 11 December: The BPMA had produced a small number of FDCs with 2 x 1st class stamps, one of each.
GBStamps blog that these were all sold out BPMA have now said that they have more and are releasing them in batches. Whether this means just the original 50 or that they did many more, is not clear.
BPMA have confirmed that the quantity total is 50, currently being sold over two sites.