The British Bechuanaland 4d. was surcharged 1s. with both types of font as a double surcharge. This is a known practice of some jobbing printers of that era deliberately overprinting a subject twice with either different type or different inks. These 1s. on 4d. doubles are listed as SG11ab and the majority of the known examples of this were discovered in the Baden-Powell family philatelic material.
History: Gaertner May 2016 lot 214 estimate €1500