British Airways has the flights which fly from
London Heathrow Airport to Johannesburg and it takes 10hrs and 45m. You can find the lowest airfares from Emirates UK, Egypt Air and Air Namibia, just check in their site and find good deals. Then from Johannesburg to
Victoria falls, there are daily flights available and takes 90 mins travel time. Air Zimbabw, South African Airways offer the cheapest deals, so you can book it online. The Victoria falls town is just 20-25 mins drive from Victoria falls airport, so you can easily get into the town and book your accommodation.
Travelling around Victoria falls is an exciting experience during
Zambia tour, so have a nice vacation.