One of the strong moments in Margy Kinmonth’s film about War Art is the way that the viewer is compelled to confront the drawings which Henry Tonks did of the facial disfigurement of wounded soldiers in Aldershot Military Hospital after the battle of Ypres and which belong to the Royal College of Surgeons.   They are extraordinarily unflinching images, informed as much by Tonks’s surgical practice as by his training as an artist (he studied at the London Hospital under Sir Frederick Treves before becoming an Assistant Professor at the Slade).