For the first overprint type, the overprints were printed in panes of 60, with only 6 in one row being printed at a time. So the six subjects differ in certain constant characters and continue down the sheet, which enables us to identify their position in the printing forme:
Setting 1: Comma after MAFEKING; F, E, K broken (K conspicuously across both legs); E of BESIEGED broken at lower corner.
No.2: Comma after MAFEKING but often looking like a period and always, otherwise, blurred; no other breaks or defects.
No.3: Comma after MAFEKING; B of BESIEGED damaged, looking like figure 8; in some copies E of MAFEKING has curved top and first E of MAFEKING lacks serif at right bottom.
No.5: No comma after MAFEKING; BESIEGED almost BESIEGFD by missing serif on bottom of E.
No.6: No comma after MAFEKING; final E of BESIEGED conspicuously dented in at left top, often appearing as if corner is missing.
In the November 1900 issue of “The London Philatelist”, a letter from the Army Postmaster in Mafeking was published which mentions the change in the font used to surcharge the stamps:
“I have, I see, omitted to explain why the type was changed: it was owing to the type being required for other printing purposes that the small plain black letters had to be resorted to.”