dji mini 2 se uk restricted to 120m help

[Droning on and on...]

One minor point, I think the 'height' limit in the UK need not be a "height", I believe the limit is " to the closest ground", meaning it could be horizontal distance from a vertical cliff or the perpendicular distance to a slope.

In the US the FAA defines AGL as the vertical distance over the ground, and bases regulation on that.

With varying topology and normals to the ground, any other definition would be impossibly complex to comply with in a moving aircraft.