They've thought of this one in the Australian AIP;
"In the event that an aircraft is required to go around from a visual
approach in VMC, the aircraft must initially climb on runway track,
remain visual and await instructions from ATC. If the aircraft can
not clear obstacles on runway track, the aircraft may turn."
Beware, however, as the technicalities of a "visual approach clearance" vary widely in different parts of the world.