The Sunni perspective on what the incidents involving where the Prophet [saw] 'forgave', and 'showed patience and forebearance rather than retaliate', and 'return good for evil', is that, it is best to follow the aforementioned examples, but a person still has a right for eye for an eye and if he chooses to implement the 'eye for an eye' he'd be doing no wrong, as it's his right.
For example, if a person unjustly slaps me in the face, then I could decide to forgive him and not retaliate for the sake of Allah, or I could return him good for evil, i.e, I do not retaliate and when I see him another time, I offer him a sweet, be nice to him, etc, and that would be the best actions that I can do in the circumstances [I'd get a greater reward for these actions, than the one of retaliating]...but if I want, than I have the right to slap him back and that would be me 'equalising up' with the person and that would be considered as justice.
So basically..Islam encourages Muslims to do the 'greater good' which is, 'forgive and forget', and 'return good for evil'...and it also teaches them that, although retaliation is a 'lesser good' than the former, it still is a right of the person as it will only serve the course of justice.
The Islamic principle of 'obeying the law of the land' will supercede any Islamic rights that are not in accordance with it..., so therefore Muslims living in Britain can act in self-defence, as the law allows, but as far as 'seeking retaliation' is concerned, when it's not done in the spur of the moment and as a defensive/extenuating act, than it has to be taken through the courts and physical retaliation in this circumstance will not be allowed.
hope this helps
The recompense for an injury is an injury equal thereto (in degree), but if a person forgives and makes reconciliation, his reward is due from God, for God does not love those who do wrong. But indeed if any do help and defend themselves after a wrong done to them, against such there is no cause of blame. The blame is only against those who oppress men with wrongdoing and insolently transgress beyond bounds through the land, defying right and justice, for such there will be a penalty grievous. (Quraan-42:40-43)