This narrow/numeral 0 variety seems quite common. Fortunately, I do have many copies of stamps of this issue. But I do not have any whole sheets which would have been more useful. Predominantly, it is more noticeable in the second O of Borneo but it can also occur in other positions. It is quite likely in the haste to produce these overprints (please refer to part 1) the numeral 0 was mistakenly used in place of the letter O. O measures up to 1.2mm across whereas 0 measures about 0.9-1mm.
The second stamp of these 2 pairs of stamps with "stop after exhibition" has the numeral 0 in the second position as in BORNE0. With both 2c stamps, they also have numeral 0 as in EXHIBITI0N.
The first stamp is the rarer P 14.5 and it has the numeral 0 in the second position as in BORNE0. The second stamp is the only stamp I have with a brownish red overprint and looks like it has the numeral 0 in the first position as in B0RNEO.
The first stamp has the numeral 0 in the first position as in B0RNEO and possibly EXHIBITI0N. The second stamp is normal apart from the extra stop after exhibition. There are probably a lot more of these variations around.