Postal Heritage Press release 10 March 2014
"The installation will take place on the morning of Monday 24 March, meaning that no Post & Go facility will be available at this time. The new machine should be available to customers from 13:00. As previously advertised, the Post and Go underprint “The B.P.M.A./ Postage Due 1914” will continue until 25 April (updated by BPMA 21 March).
"The A1 Post and Go machine currently in Freeling House - home of the BPMA’s Archive collections - will be accessioned into the BPMA’s Museum Collections."
Yes, this means that the Postage Due version of the Machin and Flag faststamps will have a different variant. The existing version has a data string with machine number shown as A1
The new version will have machine A001 so the data string will look like the one which was on the stamps sold at Stampex:
Obviously Royal Mail wanted the machines to be used at Stampex first, rather than the BPMA - although why is not clear. But if the Postage Due caption had been delayed until the anniversary of the introduction of Postage Due stamps (20 April) the new machines and the caption could have been introduced at the same time. It rather makes one think that Royal Mail wanted collectors and dealers to buy twice as many stamps as necessary.....