According to CH.Aviation plus several media sites RWANDAIR intend to start KIGALI to LONDON GATWICK by the end of 2016 or early 2017 after they were given the green light from the regulatory authorities in the UK, RWANDAIR recently took delivery of an Airbus A330-200 and in November will take delivery of an Airbus A330-300 which they intend to use on the London service.
Also it was noted that AIR ZIMBABWE again have intentions to restart flights to the UK this time with Boeing 787 from Harare to London Gatwick in 2017 but seeing their broke I can't see it happening anytime soon although I wish them well as there is a huge demand for non stop flights from the UK to Zimbabwe.
Last year a new flag carrier for Ghana FLY GOLDSTAR AIRLINES also had intentions to fly from Accra to London Gatwick with a Boeing 767 leased from Hi Fly of Portugal but it fell through at the last moment over leasing issues.
I think that over the next couple of years Gatwick will see a few African airlines serving the airport and Air Djibouti have even mentioned London Gatwick as a future destination once they receive an intended Boeing 767-300.