FCP = Fluorescent coated paper PVAD = Polyvinyl alcohol acetate dextrin gum
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wd19

WD19 - Wales 5.5p deep violet, FCP/PVAD, two 4.75mm B3 phosphor bands (Cyl 1) (Harrison/photo) - Deegam W55.1.1 - S.G specialised XW31 - Stoneham WA31 - Concise W20

Two 4.75mm B3 phosphor bands from cylinder 1 [23.1.74]
wd21

centre band

WD21 - Wales 5.5p deep violet, 4mm B3 phosphor centre band, APS perforation (Cyl 1) (Harrison/photo) - Deegam W55.2.1 - S.G specialised XW32 - Stoneham WA32 - Concise W21

4mm B3 phosphor centre band, APS perforation from cylinder 1 [21.5.75]

WD21k - Wales 5.5p deep violet, 4mm B3 phosphor centre band, KAMPF perforation (Cyl 1) (Harrison/photo)

4mm B3 phosphor centre band, KAMPF perforation