not that it made any difference in the end but i thought he was unlucky to see it chalked off, peacock had nowhere to go and i've seen plenty of similar ones given

Was that what it was chalked off for? I haven't seen it again so don't know, but I assumed it was for the play the ball because I saw nothing wrong at all with anything else. Even it was for the play the ball he motioned with his foot, albeit a token effort.

Either way, I thought it was a bizarre decision.

I think the remaining shreds of credibility Steve Ganson was clutching at blew away in the wind last night. I initially thought it was for not playing the ball properly even though he had made an attempt which is the requirement.

What is the difference between scooting out of dummy half and crashing over the line from dummy half?

It was for "Obstruction" by Peacock. I was quite surprised to see that as the reason for it being chalked off. There's a brand of No.9 who make careers off tries like that. I thought McShane had a very composed game, he's really taking his chance with both hands.

Cummings thought it was a try and couldn't see anything wrong. Ganson saw an obstruction and the "real expert" Jon Wells, gave it a special name that they have in Australia ("tunnelling" or something like that - where you burrow through the legs of the player playing the ball - even though McShane actually went to the side of Peacock).

I wait to watch, knowing with 100% certainty, that an exactly similar try will be awarded in the next few weeks live on Sky (probably to Wigan) after the refs have gone away and re-interpreted the rules.

Ganson was tracking the wrong player.

I thought it was a try all day long.

How's McShane going for you this season, i really enjoyed watch him at Widnes last season?

No doubt in the coming weeks someone will have a very similiar try given, by ganson, probably wigan.

It was disallowed for boring (Aussie term) There was one disallowed over the weekend in Australia (I think it was Brisbane) for exactly the same offence. Basically it's the dummy half using the player who has just played the ball as a shield, and he is not allowed to make contact with that player.

Obstruction?
If that's the official reason, it's wrong.
Extract from the rules (here -> - A player may pick up the ball at the base of the scrum and bore
through his own forwards to ground the ball for a try"

That, to me, is the same as "boring" through one forward at the PTB.

Frankly, I'm getting truly p'ed off by some of the decisions on obstruction this season, which appear to be based on their "interpretation" of the rules, when there is little or no interpretation required.

It's as if they're desperately looking for reasons not to give a try.

Quite.
Wigan have been the beneficiaries of one try disallowed against them in one match and one try allowed for them in another match this season ... but where the "obstruction" was virtually identical.
In both games (IIRC) the result was very close and those decisions could well have been the decider.

couldn't have put it better myself. Inevitable!

I've given up even trying to predict whether a try will be given or not when obstruction is involved