This email was sent to me by Ian Billings, in reply to the conundrum of the reproduced cylinders numbers at De La Rue. Thanks Ian this is most welcome.
"Whether or not this will make a great deal of difference to how stamps are produced, I don't know, but it is interesting:http://www.expressandstar.co.uk/2007/04/27/print-firm-eyes-stamps-contract/
Specifically:"Royal Mail will deal with three large suppliers to manage its entire print needs including stamps, labels, envelopes, leaflets and posters for internal and public use."These three companies would then sub-contract to smaller companies, of which Walsall Security Printers would be one.
"Recent discussions on the Virtual Stamp Club about USPS's arrangements mentioned that stamps could be printed by company S or its subsidiary, company B. The plate number prefix identifies the printing company, but clearly company B could run a reprint using plates/cylinders previously used by company S, without changing the plate number.
This followed discussions on USPS decision to not require new numbers for new plates (rather like the (presumably accidental) re-use of cylinder D1 for the latest 46p stamp from new cylinders. In the US the provision of a new number is no longer necessary or required, much to the annoyance of Plate Number Coil collectors, and others who use a new plate number to look for identifiable differences in the stamps. We will have to see how things develop".
Click on this link to visit Ian's Website: http://www.norvic-philatelics.co.uk