If there is an undercarraige problem indicated, and you have to burn fuel for THREE hours, and then risk a heavy landing, isn't it more logical to proceed to your destination to make the landing ?
CY Flyer, if the gear had fully retracted I would agree with you.
However if there was a warning it would indicate the gear was not fully retracted in which case you would be limited to gear operational speeds in cruise, (the Boeing equivalent is 270 knots IAS.) Also there would be unknown extra drag implications depending on how much drag there was from the gear doors or undercarriage leg and wheels. Faced with such an uncertain situation no one would want to launch off across the atlantic with nothing en route until the Azores.