12 September 2018 - Definitive reprints by ISP Walsall - First day cover of new stamps.
The contract for 2018 reprints of definitive stamps in counter sheets was moved from De La Rue to ISP Walsall. Because Royal Mail identified these as non-visible change they made a formal distribution for philatelic customers and so there is an official first day of availability.
As it happened the 2p had been reprinted twice, once with yellow phosphor bands and once with phosphor which reacted blue, but with yellow fluorescence in the iridescent security ink.
These FDCs, therefore, have 1p, 2p blue phos, 2p yellow phos, 5p and 2nd class Large stamps from counter sheets. The second image on this page shows the two 2p stamps under ultra-violet light.
More details about this on our blog https://blog.norphil.co.uk/p/blog-page_30.html