Another thing to remember is that most/all of these policies seem to have in the small print that they will not cover you for places where the Foreign & Commonwealth Countries (FCO) advise you not to travel. That therefore rules out a lot of the countries I'm looking to travel through in Africa.
At the moment some of these include (countries relevant to me taken from
Home*Foreign & Commonwealth Office):
Algeria: against all but essential travel to the administrative districts (wilayas) of Boumerdès, Tizi Ouzou and Bejaia, which are east of Algiers and Blida, Medéa and Ain Defla, which are south west of Algiers.
Angola: against travel to North and South Lunda Provinces.
Cameroon: against all travel to the area bordering the Central African Republic and Chad, against all travel along the Meiganga-Ngaoundere road and to the Belel area, against all travel to the area bordering Nigeria in the region of the Bakassi Peninsula.
Congo: against all but essential travel to the Pool region, including using the Brazzaville-Pointe Noire road and railway, against travel along the Ubangi river in the Likouala region, where the river forms the border with the Democratic Republic of Congo (DRC).
DRC: against all travel to eastern and north eastern Democratic Republic of Congo (DRC). This includes entering DRC from Uganda and Rwanda. Against all but essential travel to the rest of DRC at present because of continuing tension and insecurity. The situation can deteriorate at short notice, as happened in Kinshasa in March.
Ethiopia: against all travel to areas off the principal roads/towns within 50 kms of the border areas with Eritrea (landmines). Against all travel to the Danakil desert area bounded by the Dessie-Adigrat road, the Dessie-Djibouti road and the Ethiopian/Eritrean border. Against all travel to the Gambella Region. Against all travel to areas off the principal roads/towns within 50 kms of the borders with Sudan and Kenya. Against crossing the Ethiopia/Somalia border by road, and against all travel in the area east of the Harar to Gode line.
Libya: against all but essential travel to all areas bordering Chad and Sudan.
Mali: against all travel to the north and west of Timbuktu, the north and east of the Niger River along the line of Timbuktu, Gao, Ansongo and Labbezanga and towards the western border with Mauritania and eastern borders with Niger and Algeria.
Mauritania: against all but essential travel to the area near Mauritania’s border with Algeria, and the area near Mauritania's northern border with Mali east of Nema.
Niger: against all travel to the Aïr Massif region and on the road linking Assamaka, Arlit and Agadez.
Sudan: against all travel to Malakal and all but essential travel to the rest of the Upper Nile area. Against all travel to the Eritrean border, and against all but essential travel to Kassala. Against all travel south of Juba in Central and East Equatoria. Against all travel in West Equatoria within 40kms of the border with the Democratic Republic of Congo (DRC). Against all but essential travel to all other parts of southern Sudan, including Juba. Against all but essential travel to Darfur.
Zambia: against all but essential travel to the rural parts of the North Western, Copperbelt, Central and Luapula provinces that are close to the border areas with the Democratic Republic of Congo (DRC).