Lot 60810 – 6d reddish-purple, specialised study of the U22, V23

6d reddish-purple, specialised study of the U22, V23 and W23 control blocks neatly mounted and knowledgeably written up on 12 album pages, with 19 items including control singles, strips of 3 and mostly blocks of six, with a few larger including blocks of 8 and 24, showing a wonderful array of overprint, watermark and other control variations, an excellent basis for study and expansion