Though the Lincoln came from the Central Gunnery School, it was off for a fighter affil exercise, and loading the guns was therefore not deemed wise..... It may be that ammunition was carried (but not linked to the guns) for ballast, and I do recall reading that this was occasional practise on the type.
With regard to the Venom/MiG, it wasn't 20 Sqn (who did the Hunter/MiG manoeuvre kill in the Indonesian Confrontation) and it wasn't over Egypt.