Judging by the small size of the wing, and the apparent speed, I reckon it is a Streak Shadow. I base this on my estimation that the train is doing about 70mph, yet the Shadow is able to pull away from it with ease. Having seen both the microlight version and the Streak flying together, I don't think the microlight Shadow can accelerate that quickly and easily from 70 up to over 80mph, but the Streak with its smaller thinner wing can.
This would of course mean it is a GA version, and therefore cannot be flown by a microlight pilot.
So the knob flying the GA aircraft should perhaps get more training, eh Percy?