Brian Sinnott has updated the list of Post and Go locations and a complete list is now on his blog here.
The latest office is Dorchester in Dorset, and there are now 239 machines in 148 publicly accessible* offices. The number of machines in each office is shown but on my (Firefox) browser it almost clips the right-hand column. It shows properly in Safari. Most offices have 1 or 2 machines but there are 9 at Pinfold Street Birmingham,
Machines with codes 699010/699011 are at the Old Street PO Head Office and are also used at exhibitions.
UPDATE 16/7/12 - Cambridge (St Andrews Street) 007113 now has a third machine in the refurbished office. (Thanks SM)
This is a Post and Go Label from the new machine: 007113 3-PAG
ROC ~ Rooster ATM FDC - Republic of China (Taiwan) Rooster ATM FDC, posted on February 23, 2017 from Xansia White Rooster postal agency.