For the interested:
Camera: Canon 6D. (not Mkii).
Lens: Canon 400mm F5.6 L
ISO: Minimum. L(ow) (50).
Aperture: Minimum. F32.
Shutter speed: Minimum. (1/4000s).
Locked focused to a distant-flying aeroplane (pretty-well infinity).
Photo taken as sun disappeared behind clouds (important!) at approximately 11:10am BST (3 minutes before peak eclipse).
Developed in Lightroom Classic (2.6)