3 Phase generator 300v
The generator that you linked has 200 V, 400 Hz, 3-phase output. It is probably intended for use at an airport to supply electrical power to aircraft when their engines are not running. It is not suitable for supplying power to equipment that requires UK mains power.

A 220 V, 3-phase, 50 Hz generator is suitable for powering a 380 V, 3-phase, 50 Hz, star connected motor that is reconnected delta. A 240 V, 3-phase, 50 Hz generator is suitable for powering a 415 V, 3-phase, 50 Hz, star-connected motor that is reconnected delta.