20l. blue (pos.30), trace of double control numbers, inverted "0" and uneven control numbers with the "0" higher (not mentioned in Kountouros study). Also Grooms characteristic "0" No.19 and plate flaw white spot at the angle of the neck. Control number error combination (Kound. 38.1.f+38.2+38.7) on a plate flaw stamp. Good/large margins but one closing corner cuts stamp at lower left. Rare. (Hellas 27aNoINb20F9).