It does suprise me that, given their distinct lack of aerodynamic gravitas, we see Herons so far away from what you would be consider their natural habitat.
As a heron flies I am around 12nm from the nearest Norfolk broad and about the same from any major river complex supplying Heron grub, yet I frequently see them in the locality.
Scare them away and they take off an fly with the elegance of a breeze block, quite how they manage the distances I don't know, taxis and buses perhaps?