Mafeking Siege 1900 SG 7 Ovpt 1, 3d on 1d Lilac VF/M with Cert

1900 3d on 1d lilac of Bechuanaland Protectorate (SG 7 ovpt 1). VF/M example. Only 1800 overprinted. Rare mint. Photo-cert: BPA. (cv£1000). See clickable additional image and of certificate below.