It was lost in the tackle, onus on the attacking player to keep hold of the ball which he failed to do

Don't think Haughton tried to steal the ball though. Think he was trying to tackle/stop him. If in the opinion of the ref he hasn't deliberately gone for the ball then if it comes out as s consequence of a defender making a genuine attempt at a tackle then it's a loose carry.

I thought the ball steal rules didn't apply to a attacker in the act of attempting to score a try. Or is that just in the NRL?

If Powell had curled his fingers round the ball like he did when shoving them into Lineham's eye, he might not have lost it.

I was amused by the Sky lot, before the replay that showed the ball coming free, they said "his momentum took him over, there was no attempt to promote the ball", just as the first replay showed Powell lifting his arm to try to reach over to put the ball down.

[urlhttp://www.therfl.co.uk/the-rfl/rules/official_laws/13_penalty_kick[/url

Offence against Try scorer 9. If a player fouls an opponent who is touching down for a try, a penalty kick at goal shall be taken from in front of the goal posts after the attempt to convert the try. After his kick has been taken the ball shall be deemed dead and play shall be restarted from the halfway line. This law applies to the period during which the ball is touched down for a try and not to any subsequent period.

A ball steal when someone is trying to score isn't a penalty, let alone a penalty try. Assuming the ball comes loose its just a matter of whether it was propelled forward or not. I have no problem at all with it working that way, as IMO the current rules are too generous in favour of the ball-carrier elsewhere.