Isn't this a LONE5 - Asia/NA/SA/Eur/Afr.
You are going via LHR - I know this is allowed in terms of re-entry to transit through, but I don't think you can go via LHR to Africa and not count Europe as a continent.
Anyway your time in LHR is longer than 24 hrs thus a stopover.
Given all the above posted issues an airline (which knows the rules) nor a TA would be able to issue this ticket as it is an invalid routing.