Time of day and angle you are shooting the aircraft play a part as does the temps between air and ground or water. Wiki has a good paragraph on it. If you are at Bayswater at sunrise you run more chance or having a less difference in air and ground temp but once the sun warms the air forget it.
Cold air is denser than warm air and has therefore a greater refractive index. As light passes from colder air across a sharp boundary to significantly warmer air, the light rays bend away from the direction of the temperature gradient. When light rays pass from hotter to colder, they bend toward the direction of the gradient. If the air near the ground is warmer than that higher up, the light ray bends in a concave, upward trajectory
So it's hardly a trade secret but more of a case of getting up early. Not to mention at Bayswater you have all that water that throws even more into the mix with all that water too.
