Abraham said:
..... however it is a case in extremis especially as the death is completely accidental (being as a result of the fall after the punch, not the actual punch)
If you commit an act that was intended to cause "serious injury", and the result is death, then you are very firmly in the territory for a murder charge. Be clear - you do NOT have to intend to kill to be charged with murder.
But, it's a legal grey area. It has been extensively argued over as to quite where the line is, what "serious injury" is, and what "intends" means but, as a broad definition, if it is probable or highly probable that death would result, the charge is likely to be murder, whether death was intended or not. But, a some point, the intent to injure becomes insufficient for a murder charge. Exactly where that point is is a matter for contention, and is likely to vary from case to case and circumstance to circumstance. It has certainly been the subject of numerous cases, up to and including the House of Lords, for several decades.
But what IS clear is that if you clobber them intending serious injury, and they die, it is quite possible a murder charge will result, even if the death was "accidental" .... or rather, unintentional since 'accident' this was not. That is, in my view, eminently likely for the guys that were described as liking to chuck people down stairs, and also quite possible for a professional bouncer and boxer that hits someone as hard as this guy seems to have done.
And so it should.