Ds has always had an issue with frustration. He has improved over the last year or so since we started having lots of serious chats about his temper but in the last few months, he has started having violent outbursts again (he is a lovely, gentle boy but tends to reserve his most violent behaviour for me (or sometimes dh and dd) at home!).
What we did a year or so ago is sit down and ask him how he felt just before he was going to punch/kick/hit and then worked on other ways to deal with those feelings.
That seemed to work for a bit as he could vocalise when he got to that point and then go outside and kick a ball or shout a bit but I am just looking for other tips really.
(and before anyone says 'oh just punish him' - he knows punching/kicking/hitting is wrong but he gets to a place where he loses control of his emotions so just telling him off doesn't work over the long term)