You are correct. The eBay link goes to a CC Lee Challenger 1 Mk 3, which is a poor copy of the Tamiya kit. He probably stuck the name Airfix in there by accident or to attract attention using brand name recognition.
Airfix did rebox a Trumpeter Challenger II, which is a different kit and different version than the CC Lee kit.
This is the CC Lee kit called "Airfix" in the eBay auction.