Anyway, I have now managed to locate the image of the Machin Pane from the Military Uniforms - RAF Prestige Book – due to be issued 18th September 2008. So either it was not publicised (enough), I have not seen it or there was an embargo, if the later the embargo for this issue must now be over.
This is reproduction of : The Dambusters Crew Cover Produced by : Bradbury (BFDC) the only place I have come across a picture of the pane.
Pane 3: From the booklet will be - 4 x 1st class and 4 x 2nd class Machin definitives.
These panes will be printed by Walsall. The printing will be in litho - so the definitives will be printed in litho for the first time since the James Bond Prestige Book .