Gaff deserves some leniency.
It is not at all clear that he intended to strike Brayshaw in the head. And, Brayshaw's head naturally lowered at the time Gaff went to strike - Brayshaw's knees bent and he lowered his head slightly.
I think it is plausible at this stage that Gaff's intention was to whack him in the upper body.
I think his good record is a relevant consideration in understanding the offence.