I'm surprised at three and five year sentences for manslaughter. I find manslaughter an interesting conviction. People have been given 20 years, or have walked, after such a conviction. I agree with the vast range of sentences, which generally reflect the differing circumstances.
I suppose in each of these two cases, neither killing was in any way pre-meditated - say compared to someone who kills whilst on a burglary, or by drunken or dangerous driving. In each case, they killed as a result of some sort of provocation - an instantaneous reaction.
But I feel queasy about the shortness of those sentences. when you consider the length that, for an example, an abused woman might get for killing her abusive husband. I wouldn't regard that woman as a danger to wider society. These two men are clearly a danger to wider society, and I would far rather see them locked up than even a murderer who has committed a 'crime of passion'.