Hello Ian,
some interesting Central African knives/swords. I am not an expert by African blades but I have Zirngibl/Kubetz "panga na visu", a very good reference book. Another very good reference you can find here:
http://www.memoire-africaine.com/armes2.html
Like Miguel I think that A & B are Ngombe or Poto knives from Congo (not Zaire), C will be also a Congo knife, possible Mbole, So, Topoke, Lokele, Mba or Genya tribe. D is clearly a Saka knife, also Congo. E is most possible a Konda/Kundu/Mongo knife, Congo as well. Compare with the given link, you will find similar examples.
Personally I would clean the blades from this knives, see also inside the link, they look much better with clean blades.
Best regards,
Detlef