Okay, so it's together. That, however, doesn't mean my troubles are entirely over. The blocks are NOT lying flat in the centre, so it is going to be impossible to quilt.
Here's my plan: I'm going to wet the quilt top down, and put it in a hot dryer to see if the stretched bias edges will realign themselves. If that doesn't work - I believe it's a goner! If anyone has any other suggestions, that doesnt involve picking seams out AGAIN, then I'd be happy to hear them.