I appreciate that Malcolm and love the aircraft but why is the grass not being disturbed? It’s puzzling me👀🤔
Parallax. The camera is filming from about 30 degrees off the nose. The red/white fire hydrant? in the background is level with the left hand edge of the tarmac/concrete, so the jet efflux would be well to the right of it (as we look). We only get one view of the shrubbery directly behind it (at about 2:00), and it appears the jet is about 20m from the edge of the tarmac, and so probably 25-30m from the taller grass. You don't need much puff to get a lightweight fighter moving (two people could probably push it) so the engines are only revved up to just above idle to get it moving.
If the engines had been running at full chat the grass and trees would be moving in the jet blast. But at idle power it would be un-noticeable. You can often get that close behind jets at airshows, and you don't really notice the jet thrust above the noise and smell of burnt kerosene .