Provocation is not a defence to a charge of assault. It can only be used as a defence to reduce a charge from murder to manslaughter (it is not a complete defence). In any other case it cannot be used as a defence although, after conviction, it can be taken into account by the court when considering an appropriate penalty.
The provocation defence is only available where the defendant hears first hand of the thing that provokes them.
This is where a person in the defendant's situation, and who has the defendant's characteristics, but possessed of ordinary self control, would be so affected by the victim's words and actions as to lose self-control as the defendant did.
The provocation has to have actually caused the loss of self-control and act as the defendant did, and it is not merely an act of vengence.
The gravity of the provocation has to be assessed by reference to the relevant characteristics of the accused and then the question is whether the provocation of that gravity would have caused the ordinary person to lose self-control (viewed objectively and without the characteristics of the accused except maturity and age) [See : R v Lindsay (2014) 119 SASR 320].