Royal Mail product codes are shown below but these are not yet available to order on Royal Mail's website and probably not by telephone either. I suppose there should be some available at Stampex as that is when they are being issued.
Royal Mail Philatelic Product Code - AV025
Also on sale (not at most Post Offices) will be a Seahorses Facsimile Pack (at £8.95) and a press sheet of the facsimile sheet at £59.95. Neither of these products is postally valid.
Front page (click on to see larger) Royal Mail Philatelic Product Code - ZP004
Royal Mail Philatelic Product Code - PV001
Enlargement of the Commemorative Sheet (click on to see larger):