Why would labor never go into a coalition with SNP?
See, this is why nation-states are dumb.
They'll probably go with an informal agreement. If Labour go into a coalition with the SNP, it will piss off a lot of English voters, and rightfully so.

I don't understand your politics at all. There's so many parties that seem to actually have a chance? Here it's really easy. I can pretty much just ask you if you think poor people are just lazy and depending on your answer point you to one of your two viable options.
I feel there is a stark difference with elections in America and Britain. In America, I feel it's very oriented towards the individual leaders, with the likes of Hillary or Obama rallying support around themselves. In UK It's more party-oriented historically representing different classes (although it's quite changed now), with Labour historically representing the working class and Conservatives being middle and upper-class. I think Cameron, Bennett, Milliband are rather uncharismatic but it wouldn't matter as much in the UK vs. US.